Loftwings and Demons

I think there is a value in avoiding unnecessary hedging language, but the expression of something less than all or none is usually not hedging but rather expressing the actual realities of our world. It's very rare for all people or no people to have some specific attribute, even within a given subgroup of people, so I think it's best to avoid such assertions without compelling citable sources. Your own personal experience with a group by itself does not count as a compelling citable source, both because you probably haven't met every member of the given group, much less made detailed observations of them, and because of overwhelming bias if you're using only your own experiences to back up an assertion you're promoting.

The kinds of things I'm talking about here are 'all people in X group are...' or 'No one in Y group is...' or 'No one I've met in Z group is...'

I think it's easy to slip into this kind of language, but because what it communicates is both overwhelmingly untrue and shows an unwillingness to acknowledge one's own biases, I think it should be avoided and it detracts from messages that might otherwise be true.