Don't you mean "the kind who use proper spelling"?
If you're going to correct someone, at least get it right.
No. Both "who" and "that" may be used to anchor relative clauses with human antecedents. To quote [1]:
Most writers use 'that' and 'which' as the relative pronouns for inanimate objects, and who as the relative pronoun for humans. This widespread habit has led to the mistaken belief that using that in reference to humans is an error. In fact, while most editors prefer who for people, there is no rule saying we can’t use that, and that has been widely used in reference to people for many centuries.
In other words, my original sentence was perfectly grammatical, and in regard to the original commenter's presentation skills -- and their correlation to his employability and salary potential -- I was simply stating the obvious. But this being HN, I've been downvoted and/or flamed at least 8 times for it.
Nor is it widely adhered to, in colloquial usage.
The kind that use proper spelling and punctuation, perhaps?