The government doesn't mandate beliefs. In this case, the government denies you a platform to spread particular beliefs. It's hard to argue that leaving holocaust denial out of the discourse is losing much of value.
It's something I believe isn't a slippery slope. We have ample evidence that denying a platform to limited sets of beliefs (e.g., Holocaust denial or Nazi sympathizing) does not quickly devolve to total censorship the likes of which we see in China and Russia, which was the original argument you made.
If you're backing down from that original assertion I'm happy to argue other aspects of this discussion, but I'm not going to chase you around in a circle while you keep re-framing the argument.
