Not only is your opinion uninformed by facts, but it also shows a bizarre misunderstanding of what the presumption of innocence entails. The notion that lawyers are ordinarily obligated by the rules of professional responsibility to defend persons who have been charged with crimes and should be disbarred for not doing so, no matter how convinced they are that those persons are guilty, is juvenile nonsense.
Only in very rare circumstances, usually when for some reason no other lawyer can be found to represent a criminal defendant, can a court require a lawyer to represent him. The Timothy McVeigh case provides an example of that. Otherwise, if a lawyer believes a person has committed a crime, particularly one he finds repugnant, he has no legal or ethical obligation whatever to agree to defend that person.
Vincent Bugliosi, who led the prosecution of the "Manson family" defendants, made some scathing comments about the very sort of conduct you seem to think is so noble and wondrous. He said the evidence against these people was so overwhelming that he would have been embarrassed--his word--to offer them his services, had be been a criminal defense lawyer. He noted with disgust how many lawyers he had seen rush to try to get that job, not because they believed these depraved murderers were poor innocents who had been railroaded, but simply because they saw a chance to gain publicity and make a lot of money.