One should, if necessary to attack at all, attack the argument, not the form; but the argument has to be comprehensible. An understandable posting in Lolspeak may be cute, or tedious, but if it's understandable, I don't really care. Someone who writes "u no I iz not gon 2 rite lik dat," so that I have to spend five minutes sounding it out and playing rebus games, is not going to make for easy conversation.
And if you are trying to win an argument on your technical expertise, you lose 101% right off the top if you cannot spell technical terms relevant to that supposed expertise. If you say, "I should know, because I am a kernel in the armed forces," I will find myself doubting you.