A blanket statement is a generalization that encompasses all members of the class of things to which it applies, and may not be true for all or some of them.
It’s usually used in the same sense as “everyone” or “always”. It can also refer to an example.
Often these statements are more accurate when they’re phrased using “generally”, “most”, or something similar like that. Instead of saying there is absolutely no crime in China, one could say that there is generally less crime in China than elsewhere given its size and population. That way there can still be room for exceptions and change over time without needing to completely prove it every day.