Can we get a name for the Internet phenomenon where a post like this says "Nearly all [thing] is this way..." and then several replies are "aha, not true, what

Can we get a name for the Internet phenomenon where a post like this says "Nearly all [thing] is this way..." and then several replies are "aha, not true, what about [exception]?" If someone says "Most..." or "Nearly all...", they already know there are exceptions.