It didn't change the meaning, because everyone understood what he said. The human mind is amazing at that. If you're going to be pedantic, fine, but own up to it.
Loose means something totally different than lose. Personally, I read each as their (real) meanings and when they don't make sense I have to go back and reread the sentence.
Yes, I can figure it out, but it's no fun to have to work to read comments. May as well let commenters use 113t-speak if we don't care how hard the comment is to read.
If you're going to correct someone, you should make sure you are also correct. In addition, not using a capital letter makes it look a bit like txt speak and generally brings down the level of discource.
See: http://en.wikipedia.org/wiki/Letter_case