I get the fear of crazy looking ones like Pennywise, but how is that different from the fear of any non-clown maniac with a crazy look on their face and intent to murder? You could put a guy in a Pluto (Goofy's dog) costume with a serial killer grin on his face wielding a machete and I'd be just as scared.
I will say thought that as an adult perhaps a dislike for clowns cause they're terribly unfunny is logical. Cause someone trying hard to make you laugh especially through slapstick humor rarely works out. But I'm sticking to the fear definition of phobia and not dislike definition.
But a fear of all clowns just cause .... I don't get it.