Nobody is saying it’s wrong to be be a conservative or republican, they’re saying it’s a problem when e.g. religious fundamentalism worms its way into legislation, because the unavoidable consequence of that is reduced freedom and harm on a mass scale. The constitution defends the rights of those who choose to adhere to religious guidelines, but it does not extend to enforcing them on those who chose otherwise.
A lot comes down to the definition of “harm”. If harm includes making people feel uncomfortable, unhappy, offended, annoyed, or even just having their world view challenged, then I can see how a problem can emerge.
But…religion is more than just the form of the Christian church. I’d argue that in the case of some of the moralities of the extreme left today have reached the levels of dogmatic fundamentalism and their demands and influences on their politicians are not unlike what the religious right was doing in the 80s onward. They very much have a problem with differing views, attempt to ban books, and work to shun out folks from public life whose views don’t align with their own.
40 years ago I would have argued against the horseshoe theory but I damn sure wouldn’t question it today.
Literally I have been told that not being “liberal enough” is worse than being a conservative.