I have no education in law, and know next to nothing of its practice, but I do know that a lawyer's role is not necessarily to believe their client's innocence, but to make sure the system in which they are operating is adhering to the law even if the expected outcome is a guilty verdict.
No no those are lawyers for poor people like you and me.
When we talk about lawyers for companies and billionaires it's a completely different game.
Remember last time a lawyer said they wouldn't represent facebook because they didn't necessarily believe their innocence? Right, never happened. Because on that league, the game is to twist the meaning of words so much that the judge starts to doubt he understands the law himself.