Sure, tough guys maybe don’t wear shorts all that often on screen but are you going to remark that an Al Pacino character in a movie looks silly in shorts when that character could almost certainly murder you?
In Donnie Brasco other people are wearing shorts on the beach, making the fact that Al Pacino is wearing long pants while lounging all the more obvious and slightly weird.
In Scarface, apparently just wearing white suits is enough to stay cool on Miami Beach because he never wears shorts.
If you’re tough enough you can wear what you want.