In Finland you shouldn't generalize, because if you do people will come against you personally. Especially if they don't agree you they will tell that you are "childish" or that you are "narrow minded". This is just because they always think their opinion is the only one that is right and when you are generalizing sure you are saying your opinion quite straight.
"Everything is not that black and white", means from my point of view "my opinion is better than yours". Finnish people use this a lot, because they want to control your opinions. But truly I think they say this, because they don't except your opinion. Who's being narrow minded?
This is probably same in many country, but what I have experienced is that in other countries people try to bring some other perspectives to my head instead of starting to give me names.
But at the same time this is so funny, because in Finland people talk lot's of crap behind each other. So what I mean is that when someone says something with a loud voice - it's wrong. But talking crap behind is ok.