You are archaic. I _almost_ said 'your archaic' there. Grammar, spelling and punctuation are often arbitrary rules that are difficult to grok, except with extensive experience with them. One of the best ways to discourage that experience is to make everything about everything and mark down an otherwise-excellent essay due to spelling.
Note that I am not saying that we shouldn't teach those things (and schools do teach those things), but that teaching them in a lower-stakes fashion where people are able to succeed at the core learning goal (argument in this case) without bouncing off of the Wall Of Spelling is a much better approach.
Note that I am not saying that we shouldn't teach those things (and schools do teach those things), but that teaching them in a lower-stakes fashion where people are able to succeed at the core learning goal (argument in this case) without bouncing off of the Wall Of Spelling is a much better approach.