Get off your high horse.

If expecting basic human decency puts me on a high horse, then I don't intend on coming down.

I provided direct counterarguments with a couple lines implying I thought he was being disingenuous with his criticism and you focus on my tone instead.

Maybe because you decided to immaturely take a jab at his reading comprehension instead of focussing at the topic at hand. That's more than a little distracting to me

You could have replied to the points I made

Why would I want to have discussion with someone who can't rebut something with insults?

and if it's true I was being "rude" I at least had the courtesy to take OP seriously enough to do this

Taking him seriously = telling him that not only is he wrong, but he is so wrong that he is probably illiterate?

but it's not cancerous because it's full of assholes but because it's full of pretentious idiots who want to be "critics" because they can write essays on their Internet blogs, /a/, and reddit.

I very strongly disagree with that. Are there many pretentious anime fans? Sure, but I'd take pretentiousness over inability to discuss civilly and like normal human beings.

They do find out that soul gems literally contain their souls and they still exhibit a degree of disbelief that they turn into witches even when Homura explains it immediately after Sayaka turns into a witch

You're telling me that these scared, naive little girls who had no reason to distrust Homura in the first place would CONTINUE to distrust her after being shown that? Ridiculous. And even if that was the case, it's inexcusable for Homura to not attempt that.