[lazide]

Again, ‘it depends’. You’re generally correct, but ‘bills of attainders’ laws (aka targeting specific individuals) along with the ‘equal protection before the law’ clauses make it unconstitutional to target specific individuals instead of classes of behavior, and that is the general theory behind it not being ok to do true selective enforcement (aka Bob gets charged for something Joe does openly all the time).

Like pointed out in a sibling thread though, essentially impossible to prove, let alone get anyone to care about, and useless as a defense unless someone is being stupidly blatant about it.