Not at all. If you want to say that all Japanese people have an evil trait, then by all means go for your life, but you're making a scientific claim in that instance, because what we know of genetics. It's no different, or less offensive as saying black people aren't as intelligent as white people.

If you want to generalise about English people moaning about weather, or cueing, then that's different - they are our idiosyncrasies. But when you dismiss a whole people as being this or that, then you need to do more than just state it.