I see this kind of thing as a lark. People should always strive to be as eductated as they can. Just because you CAN do something doesn't mean you SHOULD do it
(trust me on this one, I'm young, and savvy in the ways of learning these types of lessons)
I think that correcting someone's grammar/spelling issues is kind of like a helping hand towards making sure every voice is heard with the true intent that it wishes.
"Witch do you puffer? No wing weather the whether is going to spit it's furry, or if its going to be a descent day."
(reading something like this would eventually drive me crazy)