Not only disrespect to, but contempt for characters and their lives is a deal-breaker for me. I do not stick with stories that try to sell me the old "but it raises the stakes and makes it real" chestnut. If I can't feel invested in something because I don't know if possibly the only character I like or identify with will make it through the next page, I don't feel the need to keep up with it or its creator's work if they make it a pattern.
I don't feel that perceived rudeness or conflict between an author and people who leave comments is necessarily anything that damages a comic for me, because there are a few things to consider:
1) Just because someone leaves a comment doesn't make them a fan or even necessarily a reader. They could just as easily be someone who stumbled upon it and is speaking out of ignorance or contempt themselves, or someone who has been prompted to troll the comic. It seriously does happen, unfortunately.
2) If an author has not asked for critique or has specifically asked people to avoid certain topics -- or if people already know certain topics set the author off -- it's more than understandable if said author responds less than favorably to that very thing being brought up to them.
3) In most cases, webcomics in particular are basically provided entirely for free, on the hopes that people who like it will actually be kind enough to pay for the hard work that went into it. Unfortunately, there are nonetheless a lot of people who will stop by expressly to troll a comic and its author, and others who simply don't understand the concept, or want to undermine the author's ability to actually make a living. It's sad this is a thing, but here we are.
Most of all I'd like people to understand this: when there's a conflict of any kind, there is always one side, the opposing side, and the truth of the matter. Most people coming into a situation like this know only a very skewed perspective and don't get -- and aren't owed -- the rest of it. It's a Rashomon situation, and in text, a lot of the time you don't have the advantage of tone that voice gives. That leads to more misunderstandings and seeming clashes than I can count. There are also certain groups and people that just don't get along very well. Plenty of people will just react whenever they see any hint of conflict and assume the worst, usually about the person with a phrasing they don't like.
In short (I know -- too late! 
), unless an author goes out of their way to be a total assbag to fans and readers, I'm not going to assume that they're a total assbag. We all have bad days, bad topics, and people that just rub us wrong. There's a curious tendency that I find, and most especially in the US, that people are expected to be pleasant and cheerful at all times, and honey -- that just ain't gonna happen. But I agree that people shouldn't go out of their way to be unpleasant if they are at all capable of being at least civil. That goes both ways in this exchange.
I do think that a repeatedly, excessively hostile author can damage a comic's reputation though, especially if their approach isn't offered any explanation.
On other notes, I don't really regard comics highly if they're offensive in ways that are neither entertaining nor providing of any commentary or analysis on the matter. I don't respect authors who have knowingly and purposely paid me professional discourtesy. Naturally, I don't support people who have discriminated against or further discriminatory attitudes against me or people like me, but that's kind of a no-brainer I guess.
I feel like this could be summed up by "don't be a dick and I'll probably have no problems with your comic"! These are things that I have personal exception to, yes, but they're also things that I feel can be damaging for a comic's reputation. I don't find a problem, generally speaking, with people drawing from experience with people or types of people that they dislike. If it inspires them and they're making a good comic, then they're still making something engaging enough for my satisfaction. Write what you know, it's been said. Of course, there's a fine line between doing something constructive with that feeling and just bashing people.
All said though, reputation doesn't always affect a comic's success -- or anything else's -- one bit. So mileage may vary.
