Do you not quite understand that the issue is being ignorant of the topic discussed and not the spelling or grammar used to debate that topic?
First criterion is whether I can understand the argument without having to do more than my fair share of the work. If it passes that, I look at the substance of the argument, and let the fourth-grade English peccadilloes slide…
Exactly. I have found a correlation between people with horrendous communication skills and how inferior their arguments are. But it’s not necessarily so. That said, while I won’t dismiss an argument as wrong because of its wording, I may well decide I don’t have the energy or inclination to machete my way through a thicket of poorly constructed thoughts. (Typos and misspellings I notice, but they’re not a big deal.)