> Atheists frequently evangelize. It is a religious belief.
They evangelize, but its more of ideology that concerns religion rather than just a belief. The main problem with atheism is the definition: absence of religion, this is such a derogatory word as if believing in deities should be the norm. Agnostic is even worse seat: declaring that you have no clue but probably are somewhat spiritual. If you don't like religion say proudly that you are antitheist!
Calling atheism a religious belief is as disingenuous as describing science as a religion.
It is possible to be religious in your science-based beliefs, but that does not make science itself a religion. If someone believes something only because "scientists" said so then they share many of the qualities of religions. I would shy away from calling even this a religion, however, as these people are willing to change their belief if the scientific consensus changes.
Furthermore, merely evangelising is not enough to make something a religious belief and it would be an abuse of the language to conflate them in that way. It is completely reasonable to evangelise scientific ideas, and it would be wrong to label that act as a religious one.
Atheism is not science, but it shares a common tenet; both atheists and scientists are willing to change their belief if shown appropriate evidence. Atheists can evangelise for many reasons, but those reasons need not be religious. For example, atheists may believe that religious teachings promote the worst aspects of tribalism and actively harm our society. An atheist can evangelise that the argument "My god is better than your god" is a pointless source of discontent in the world, and want to remove the source of that discontent, without being religious.
Of course, there will be people who shout "you're wrong because SCIENCE!!" but the religious nature of those people doesn't magically transfer to the beliefs they hold simply because they hold them.
> Atheists frequently evangelize. It is a religious belief.
It isn't, and it's insulting to say so: You're imposing a category on people based on deliberately misunderstanding their worldview. Atheists say their lack of belief isn't a belief, and saying otherwise is insulting.