I think there needs to be a balance struck. When you can google pretty much any brewing issue and an AHA link comes up among others, it's safe to assume that a few thousand people, many of them non-forum members, are getting their impressions of AHA (and info) in part from our posts. So there is an obligation to at least try to come off coherent and correct. But at the same time, crossing over into belittling or embarrassing people obviously isn't ok. After all, we're just making beer.
Personally, I read and re-read my posts to be sure my grammar is good, and often edit for that. But grammar and spelling come easy to me - there are people that struggle with grammar and spelling who are far better at higher math than I am.