Really, where to slash haters get the idea that we slashers don't respect the canon material? The simple fact is, we slash because we love the canon material, love the characters, but want something that canon did not show.
Let me put it this way, we already know canon, therefore are complacent about it. Complacency breeds boredom and boredom sends us off looking for something new, different and interesting. Slash is different - different that canon at least - therefore interesting.
Another thing, a fan's sexual orientation does not mean that fan can only read fic that fits only into that orientation. Let me explain my point of view on slash:
I am straight. By default, that means men are sexy (to me). One man is sexy, two men is twice as sexy, and two sexy men together is more than the sum of it's parts. It's sexy squared.
It's not just the sexy factor that makes slash appealing, it's the character combinations. I like Ultra Magnus. I like Optimus Prime. I don't like Elita-1. Do the working out there - Optimus/Magnus will always be more interesting to me than Optimus/Elita, or Magnus/Elita.
I don't always have this problem, over in Final Fantasy VII, I really, really like Aeris Gainsborough. I am also a fan of Cloud Strife. Now I first entered the FF fandom through the Sephiroth/Cloud pairing, but I can easily say that if someone started a Cloud/Aeris resurrection fic that wasn't ridiculously sappy, then I'd read. Honestly I really find it down-heartening how in the OT4 of SHINY (Seph/Cloud/Zack/Aeris) that Aeris gets shoved off with Zack all the time and gets almost no smut with either Cloud or Seph. An even foursome that does not make!
I am less of a fan of Tifa Lockhart than I am of Aeris, and I don't like reading her with Cloud or Vincent, but give me a fic with her paired with... say, Cid? HOT. Cid Highwind doesn't get enough love in the FF fandom.
But not all my fandoms are so lucky - they don't have a female I like to the degree I love Aeris, and sometimes they don't even have any secondary pairings that would be interesting to read the females in, like Tifa does.
This is a matter of character preferences - it doesn't mean I hate Tifa if I don't want to read her with Cloud, it doesn't mean I hate Elita-1 if I don't want to read her with Optimus. I just am not that interested in them, or their canon pairing.
I actually don't like my slash warping characters ridiculously girly - it's OOC. Oh, I am very tolerant, more tolerant than a lot of other people seem to be. I am a fan of at least two TF writers who get slammed as writing the characters OOC, but what I see is a really good, dramatic, angsty story, that maybe takes a few liberties with the characters. It's not like it's the extent that badficcer fanbrats on FFN do.
But it just really gets at me that people can be so mean and vicious about slash, and their hatred of it. Maybe this is because I don't see the point of putting out that much energy for negative feelings, but then I tend to be apathetic about a lot of things and don't see the point of putting out an excess of energy for something unneeded in any circumstances.
I just... think it's stupid. If you hate slash, don't start yelling at us slashers for it. It annoys us as much as our love of slash annoys you. Go back to your safe little het communities, take all slashers off your watch lists and flists and fool yourself into believing we're too far away to scar your poor sensitive brains. Oh, and on that last point? Rule 34 is a fact, and if you're so harmed by people slashing your childhood favourites, then get a clue, grow a thicker skin, or GTFO the internet, because all your dearly loved childhood favourites have slash, and probably have disgustingly kinky fanart too.