You are right, of course. Maybe those of us who can't help picking up these glaring errors should adopt a whole different mindset. There's a good chance that said posters may be more caring, more giving, more productive, etc. than the grammar police.
Anyway, I don't mean to preach---it also rubs me the wrong way!
No, they are wastrels that should be horsewhipped.
/johnny
Perhaps.......then again, those of us who don't want to see our mother tongue bastardized into a gutter language, just may be the more caring ones.