^He didn't really quit so much as have the issue forced upon him. He got disbarred.
Indeed. He was notorious for various antics, which got the Florida Bar pissed at him. So they brought him in and basically said "Give us one good reason why we shouldn't force you to submit all of your future filings to another lawyer to sign before we consider looking at them." He submitted a variety of documents which included:
"Swastikas, kangaroos in court, a reproduced dollar bill, cartoon squirrels, Paul Simon, Paul Newman, Ray Charles, a handprint with the word 'slap' written under it, Bar Governor Benedict P. Kuehne, Ed Bradley, Jack Nicholson, Justice Clarence Thomas, Julius Caesar, monkeys, [and] a house of cards."
In short, he went absolutely nuts. The Bar even described his motions as "bizarre and idiotic." After he continued to freak out at various politicians and judges (often accusing them of distributing pornography to children and stating that any complaints against him violated religious persecution laws because his advocacy is motivated by his faith), they permanently disbarred him. He simply can't practice law in Florida ever again, and he won't have much luck becoming a lawyer elsewhere.
He responded with an email to media outlets speaking in the third person stating that he was being disbarred to stop him from filing a civil rights lawsuit, and actually tried to use the "It doesn't count" argument to state that he would go back to practicing law in Florida and dared the Bar to stop him. As far as I know, he has not tried.