Considering how little sense the first post made despite having each individual word correct, I think there are much bigger things to worry about than a rule creating a distinction between typing quickly and text speak.
If someone's post is pointless and very few words are spelt right, then they'll be infracted. If it is on topic but misses a few letters in an occasional word, it really doesn't matter.
Multiple question marks and gigantic red text is quite annoying too. Glass houses and all that...