Welcome to the internet, where spelling mistakes, incorrect use of words, poor grammar, are all part of it. Not everyone is an English scholar. Mixing up there, their, and they're, and your and you're, is acceptable as long as the general meaning is understood by the reader. You have to accept it, or stay off internet forums - simple.
The only thing I ever comment on concerning posts is when someone writes 30 lines of text with no commas, full stops, or separate paragraphs, as it is very difficult to follow, but I don't slag the person off, I simply suggest they format the post to make it more legible. I never criticise poor spelling by other people