Okay, speaking as a gay dude who's been right smack in the center of this very conversation for pretty much the entirety of his career, I want to weigh in.
There's nothing wrong with anyone writing characters that aren't like them in real life. It's patently ludicrous to have a problem with people writing characters that are different from them, which is what this boils down to. We all need more representation, and gay (etc.) characters aren't always going to be good guys, or well-written, solid protagonists. I will be honest, even the "magical minority" role isn't always a bad thing, especially for gay guys dealing with straight characters and audience.
People getting used to, and being used to, gay characters being around is ultimately helpful in a social sense, and it gives people valuable exposure to a life different from their own. Yes, I agree -- homophobic writers who simply (ab)use gay characters are not helping. Characters invented solely to be abused aren't helping. But those are a tiny minority. In fact, in my fifteen-plus year formal career, I can only remember a single creator I ever became acquainted with who had that attitude. The image of "straight girl writing gay guys but being a total homophobe" is largely mythical and has been blown far out of proportion, largely by people who just want an excuse to dislike BL on the whole.
And you know what? I have no problem at all with writers that just happen to like pretty dudes and want to write a story about them, even if there is some objectification in it, because these characters are not actual people. As long as those authors aren't phobic in real life, there's not really a problem I can see. We all write characters different to us -- sometimes far outside of the realm of our human experience -- and there's nothing wrong with liking what we like or wanting to see what we want to see. Aesthetic appeal is a large part of not only marketing, but also art in general. Also, gay creators do it too. In fact, they do it all the time. That's pretty much 100% of all the gay-oriented comics I grew up with: gay dudes creating characters they find appealing and giving them lots of opportunities for naughty times. It's pretty hypocritical if I somehow decide that only my fellow queens are "allowed" to do that!
Sometimes stories aren't the perfectly healthy relationships we'd like to think we're interested in; and sometimes we're not interested in healthy relationships in the first place! We can say "that's so unhealthy" all we like, but it's fantasy and if it interests us, then it interests us. Even just the fact that people are finally interested in writing gay characters having relationships is so important. For years and years and years, we were relegated to the "it's cool if you want to participate in our straight-people adventure, but we don't want to think about you actually doing romance or anything" department. We need more gay relationships. Healthy, unhealthy, kinky, whatever. This is fiction. As long as it's fiction, who cares! People should grow into adults that can comprehend the difference between reality and make-believe and, furthermore, understand the essential need for empathy between people of different circumstances and lifestyles. Fiction can help that. Art can help that.
I will also add here that it's important to me that gay guys are represented more, because most of the time? It's the "safe gay" of lesbians -- or bisexual women, that way the adolescent straight-boy audience think they have a chance to be included -- that most series use. There aren't enough gay dudes out there that actually are showcased a little bit. And yeah, I don't have a problem with a little objectification, as long as it's not malicious. These are fictional characters you invented. They're like action figures or dolls; you should have the ability to do with them as pleases you. If you want two pretty guys you like to have sex, you should be able to have that and enjoy it. It happens all the time with female characters of every kind, and it's to a point now where any type of "hey look at this, aren't these guys hot?!" is helping, even if only a little bit, to even out the scales of perception.
BL and gay erotica has helped immensely to broaden the field and broaden representation of gay men, at the very least. I grew up in a time where there was a huge amount of just...homogeny. If you wanted gay stories that had anything going on, they were usually tragic ones due to the influence of mainstream society and the desire to appeal. If you wanted gay comics or art, there was only lumpy-muscled Greek statues gone horribly wrong, with a heap of priapism.
When I was first exposed to Japan's gay comic scene, I was stunned and inspired: here was a far greater diversity in stories featuring gay men. And even though some will claim that the characters in BL are just "thinly-veiled women", I feel that saying that is much more problematic. Gender assumptions, much? I'm glad to finally see a diverse (and frankly, often more realistic) variety of personalities for the characters involved. There are some problems with Japanese attitudes toward gays, most especially the prevalent assumption that gay = transgender woman in a man's body, but even that is changing rapidly with the age of information.
And that's ultimately what helps most: information, understanding, empathy, and above all people knowing we exist. More representation in stories will help that, and I think it's even better when the stories revolve around gay characters, gay relationships, and yes, even gay sex.
Write characters who are way outside of your zone, outside of your experience. Write them like people. Don't be afraid to write them. You might make mistakes -- that's fine, as long as you're not malicious in meaning. As for readers: if you don't want to read it, don't read it! If you see someone clearly making an effort and doing what they feel is a good job, maybe offer some advice if you think they need it. But above all, no matter who you are in this equation, be kind and try to understand that 99.99999% of the time...people writing BL, whether they're gay, straight, queer, whatever...are not out to be harmful. Even if they're just writing something they want to see, there's nothing wrong with that.
Write the story you want to see instead of complaining about it not being out there for you. It's like that old saying about lighting a candle instead of cursing the darkness. I can't really be too harsh on someone who actually goes to the trouble of writing that story that they want to see. If I find the story offensive, I don't have to read it or promote it. If it's toxic, then I can always discourage others from reading it or, if I choose, I can contact the author and talk with them about their motivations behind doing it.
But ultimately, I've seen far too many situations where it all boils down to a gatekeeper mentality. Either that or kink-shaming, which is especially vile when it's fiction. It would be like someone trying to insinuate mystery writers are all secret murderers in most of these cases. Just let people enjoy what they enjoy unless they're going out of their way to be toxic. Most times, you will find that there is no real malice, just sometimes a little ignorance. And ignorance has only one handy solution: information and education.
That's just my two bits. 
