Hypothetical question: What if said 'religion' calls for the killing those who try to leave said 'religion', or for killing those who will not convert to said 'religion'?
Is this a 'religion'?
Is this death-cult covered by the 1st Amendment?
Islam is no more or no less a "death cult" today than it was before the Cartoon Riots or 9/11.
Since those times a lot of Christians have read English translations of Koranic verses on the internet and taken them literally.