Also, it's survivorship bias, to a degree. Being nice is just as much tool as being smart, and you can wield it with intent that is just as malicious. Truly successful people have to wield many tools successfully, it's only natural that one of the easiest to master is commonly used.

You never know what people's intent is, and you should assume the best until proven otherwise, but like you say, a spade is a spade, and being nice is useful to the people being nice.