I think Mike Tyson’s lisp wasn’t physically visible and during his time, there wasn’t any internet, so anyone who mocks or bullies are irl and might get punched in the face. His career does not involve speaking and even if he speak in interviews, it’s because he’s successful so no one cares if he has a lisp or not. Even pacquaio with who has trouble speaking in english, no one cares if he is barely understandable, he still commands respect because his career is in sports. Unless you excel in other things that do not involve speech, you can be successful