Religion gets away with what no political party could
Imagine you've been invited to a political meeting at the local branch of some political organisation. At the entrance you are given the party's manifesto, and you start to read it.
The political party demands unswerving allegiance to 'The Founder'. You must emulate his lifestyle. You read more, and find that his lifestyle consisted of murdering his opponents, calling for the abolition and punishment of liberal lifestyles, 'confiscating' goods and property from the unworthy, waging war on all opponents, and despising Jews and other minority or 'undesirable' groups such as gays.
Indeed, the party even calls for the setting-up of a whole new set of laws that effectively abolish the notion of democracy. The manifesto calls for the setting-up of a single 'nation' devoted to the cause, with the rest of the world being seen as 'leg room' and its inhabitants lesser people. Five times a day you are expected to perform the ritual symbolic act of allegiance to 'the motherland' and, of course, The Founder.
And to cap it all off, the party even has its very own 'party youth', who are specifically indoctrinated in the ways of the party at educational establishments run by the party.
This manifesto reads remarkably similar to another great rant you can think of.
But no. You haven't entered some smoke-filled beer hall in 1920s Germany. You've simply entered a religious establishment in leafy suburbia.