The way I see it, as long as no one's getting hurt, fandom and fans can do whatever the hell they like. Let them ship whatever ship they like, let them shipped the messed up inappropriate stuff, or not, whatever. As long as it stays within fandom and doesn't escalated into threats against other fans or the creator, have fun. Most fandoms are pretty self regulating and have similar tastes anyway. You'll find people of similar interests are drawn to the show, so often there will be some level of unity.
This is 90% of a time the problem of the writers just shoving a woman in and expecting people to accept her as the love interest without any characterization,or being an abusive tsundere type or similar. And in my experience, a pretty outdated trope. While the accusation gets thrown around a lot, very few fandoms I've been part of in recent years have fallen into this despite constant accusations. And it's not just female characters shippers get accused hating. A show I'm currently watching and currently airing just introduce a male and female childhood friend of one of the fan favourites, cue accusations that the shippers don't like them because they're a threat to the no1 ship in the fandom. In fact, the hate comes from the fact that most the shippers of that ship have read the novel they're adapting and know next episode they will stab him in the back (literally) despite him doing everything to protect them. But no, it's obviously because of the ship.
I think fandom and shippers are getting more mature while the reputation they have is still pretty poor. Of course there are places where it gets out of hand still, but most fandoms are just nice places with shippers just enjoying things. And 90% of ship are based on some kind of chemistry.
As for sex, that depends on the story. There's a trend for modern shows to just involve as much sex as possible and to show it. And that's fine once or twice, but I quickly get bored of seeing people have sex every five minutes and turn off the show. In the right place, a sex scene can be really powerful. In the wrong place or used too often it's just boring and five minutes of show I'm not getting back. A series at the moment, it's implied he had sex with the nurse for special treatment. They didn't show it, showing it would have been a waste of time, as the absolutely casually implication is far more amusing than showing it ever could have been.
It also sort falls into show don't tell in some way sometimes. If you need to tell us about an entire sex scene every time it happens rather than show us the effects or relationship, it's questionable.
