Earlier quoted context omitted.
I suspect that people don't fall into such neat categories. You could pose a similar question re: lawyers whose bread and butter is protecting and representing people associated with organised crime (the kind of individuals represented by Maury from The Wire or Neil Mink from The Sopranos). Are they lawyers who developed a slippery version of ethics & morality, or people with loose ethical standards who entered law?…
What? Representing criminals is not unethical or 'immoral'. Period. Protecting criminals legally is not unethical unless you are knowingly doing something illegal yourself. I imagine that most layers are just doing their job and getting paid for it. Bringing morality into that equation makes no sense in a legal system that has little to nothing to do with morality.
A system that didn't need to hold a trial or give the mob boss a lawyer would be irredeemably immoral but one in which they go free is a shittier world. I don't envy anyone trying to remain moral while walking that line. I don't see how anyone who specialized in such clients could live with themselves.