The word you’re looking for is “ideology”. All religions are ideologies, and atheism is an ideology, but to call atheism a religion betrays a lack of understanding of words.

Heavy ideologues, of any type, are exceptionally dangerous.

Having made this argument to various people IRL, both terms “ideology” and “religion” are equivalent rhetorically. It depends on what these words mean precisely to a given person in particular but they are equivalent/interchangeable for the purpose of this argument broadly speaking in terms of the rhetorical core.