I'll bite, (I tried to bite my tongue all day).
Mr. Wallace, (with respect)
The harshest criticism I would have for this is that, for someone so concerned with maturity, that neither your tone, nor your decision to make such a posting at all, strike me as particularly mature moves (what's your problem? you sound like a displaced, disgruntled English prof who has to make himself feel smart by putting down others).
Aren't online posting boards supposed to be relatively informal? I'm sure the people your accusing in this message would be careful about spelling and grammar on an application form, or a graded essay, but does you have to be so anal about discussion taking place in an informal setting?
You take a person's disregard for proper spelling/grammar as an indication of their maturity. Shouldn't you be looking first and foremost at the content of these messages? If some guy was posting messages like, "I want to get into the CF so I can get a gun and shoot some Afghanis", well then, that would be immature sir. Likewise, if someone was asking questions, like, "how many times have you got l#$d just because you wore the uniform", or something like that, it would definitely be a sign of immaturity. I think then you could justifiably call someone immature and question their motives.
Your decision to attack people's personalities based on innocent mistakes strikes me as a borderline malicious attack (literally, "to the person"). In other words, rather than criticizing the content or logic of the postings, you take their grammatical mistakes as warrant to attack the character of the people making the postings. You equate grammatical mistakes with immaturity of character - which isn't really a justifiable argument at all. I might remind you that a person's grammatical mistakes are not sufficient data on which to determine maturity, or immaturity, of character.
Thank you
Ryan