[vog]

So what? Is "smartness" an excuse for the unwillingless to learn productive (or at least non-destructive) social behaviour?

If anything, I'd argue it is exactly the reverse: From people describing themselves as "smart" I expect the ability to learn this even more.

They are definitely not too dumb to learn this: Internalizing some basic rules of social behaviour is not harder than learning a new programming language or familiarizing with a new framework. It's not because they are unable, but because they don't care and got away with it so far - by which I mean they didn't have to face the consequences of the damage they created in the past. That's why any reasonable manager (or community leader) needs to create an environment where they have to care early on, before anything significant happens.