Comment by CRConrad

> For one thing, you jumped from "this kind of person" to "these kind of people", without supporting evidence.

Not much of a jump: "kind" at the very least strongly implies the plural already. If you mean just one person, you say "this person", whereas "this kind of person" means "this person and others like him". AFAICS "this kind of person" and "these kind of people" are pretty much synonyms; the only difference between them is that the former is grammatically correct.