I can respect that you only like canon pairings, especially for the reasons you've stated. But — well, for instance, do you also object to crossovers? AUs? alternative timelines in which the fic goes 'what is this had happened instead of this'? the main point of fic is that we're extrapolating from canon to make something different. If we expand your way of thinking, pretty much all fanfic is OOC on some level. And if we only stuck to fic describing what's already in the canon, it would get pretty boring pretty fast.

If a character is shown as being down with the opposite sex I don't default to thinking they swing both ways and I think doing so is just stretching for one's purposes

But that's because you're (apparently, please correct me if I've misread what you've said upthread) straight yourself. I'm bisexual, and my default is that a character, if not otherwise stated, can swing pretty much any way they can. In my perspective, I'm not stretching the truth for my own purposes, just like in yours you're not stretching it for your own either. But the fact is, we both are. Our own sexuality affects the way we interpreting characters. And that's fine! what's less fine is shaming other people for shipping two men or two women because you happen to default them to straight.

Frankly, that's what I don't get about this thread. Why don't you just scroll on? where are the kicks in shaming people because they interpret characters differently than you do?