In your opinion, should all politicians know how to play chess?

King Khusros II was a violent man, who waged war and executed people with little provocation. As such, one could interpret the quote as meaning that anyone who plays chess is prone to psychopathy; therefore, chess should be avoided by any sane politician! (n.b., of course, one could argue that a "king" is not a politician in the purest sense, but, that's for another discussion!)

No. 

It would be dangerous if they properly understood how to use their stupidity 

That's like asking if 3 year olds should be given assault rifles. 

It's a good thing that their stupidity is balanced by their incompetence. 

YEs. this is a must-know! 

I assume not every politicians know but they could learn fast.

Won't do them any harm....

I don't live in a kingdom, so no, I don't think it applies. 

This is an old quote and in the modern day, a ruler needs to know the problem of the country and the solution to them instead of staying busy in playing or studying how to play chess.