I would not go as far as to say that they are as vulnerable as any non affiliated prisoner as some inmates do look up to them, and in some fed prisons they have decent numbers. I'd say the biggest issue is guys thinking "Hey he has money" and targeting them for extortion as happened to Gotti, supposedly Merlino in Beaumont, and others.

It is obvious they are not invincible by any means, and have to abide by the prison gangs politics. It is simply a different environment.