"People are dumb" (absolute, unqualified) vs "Most people are dumb" (absolute, qualified) vs "Most people I've met are dumb" (relative, qualified).
A comment like "people are dumb" is usually assumed not to be taken literally, but when you quote a study and say something like "men don't read online dating profiles", you're now in a very different territory, and the misuse of language could give the impression of a deliberate false statement (i.e., a lie).