I think if we are annoyed, we should ignore it- though it irritates me to no end. It's not important that someone use correct grammar to me if they are simply putting a message out there on a forum.
If it's really bad, I won't read it, and that's the unfortunate consequence of putting less effort into what we are writing for others- some people don't care to read text without capitalization, punctuation, etc.
When it comes to a their/there/they're, too/to/two, its/it's error, I generally assume it's someone who never learned the correct form, and while I don't like to look at it, it's not going to make a whit of a difference in anyone's life that the wrong form was used here on BYC.
It's not for me to judge, not for me to care, and I simply go on my merry way. Life's too short to be upset by it! It's soooooooo not worth any derision or divisiveness within our lovely community of people brought together by chicken-interest!!
Let's get on with gettin' on and be delighted to have each other to share the chooks with, for Pete's sake!!
...and keep in mind, while I always try to go and edit my posts for mistakes, noting that I'm a grammar nazi, it's tongue-in-cheek, and it only applies to me! I don't edit others except when I'm paid for it!!!