I don't think it's the fact that you correct them, I think it's HOW you correct them. I honestly don't have a problem with being corrected if I make a mistake, but the very confrontational style that you tend to use does make you come off as rude.
Here's an example:
In my Time Deck thread, I stated it was "well rounded" which it obviously wasn't. I meant that it was well rounded for a Mono-Time deck, and not just in general. You came in and pointed out that it wasn't "well rounded."
You said in the title that this deck is "well-rounded" when in fact it's the opposite of that (like all mono-decks). In a situation like that I have no other choice but to correct you, and I really don't care how many enemies I make by doing that.
This highlighted line comes off as, and I think many will agree, quite rude and maybe even a little self-rightous. Now, I've no problem with you, so don't take any of this the wrong way, it's just that many people DO see you as a little rude and insensitive because of posts like this one, which you've posted quite a few of.