The difference is the faith of a moderate Muslim makes them an asset to the community.
It's perfectly true that extremists of all kinds tend to disguise themselves. The problem arises when this is presented as a issue peculiar to Muslims. Or worse still, as above, when people aftempt to stigmatise the very category of "Muslim" to the extent of saying the only way to be a good Muslim is to be an ex-Muslim.
Prejudice takes many forms and this kind reminds me of assimilationist anti-Semitism of nineteenth century Germany. It was argued that Judaism was a destructive ideology not really a religion (sound familiar?) that was incompatible with European values (sound familiar?) and the only way for Jews to be acceptable was to give up their religion because it was inherently wicked. (Sound familiar?)
Many Jews responded and converted to Christianity and adopted the dominant culture, many fighting for Germany in the First World War. But of course anti-Semitiam didn't stand still. When the Nazis came to power it was no longer acceptable for Jews to renounce their heritage and beliefs. Anyone with a practicing Jewish grandparent could be convicted of being a Jew whether they themselves practised or not.