Sounds like an argumentum ad Hitlerum by zimdog.
Of course his analogy is flawed as usual. It attempts to elevate islam's status by presuming that the mahometan heresy is anything more than just that - a heretical perversion of two previously existing religions obtained by falsifying their doctrines and forcing them upon unwilling converts.
When the argument in question concerns sending law-abiding citizens to concentration camps based on their religious and/or ethnic background alone, I would say that the issue was ad Hitlerum before I rejoined.