Why do religious people desperately want to class Atheism as a religion?

[Esquilax]

Sure but what some see as "convincing" others see as "unconvincing".  it's purely subjective.

Subjectivity, however, does not preclude upper and lower bounds. For example, regardless of your standards, I suspect you have minimum and maximum tolerances for credulity, that roughly align with everyone else's. Were you to see someone standing in front of an object, staring right at it and denying that object's existence, I would think you would think that person is being unreasonable by being unconvinced of that evidence. Likewise, were you to see someone convinced of an obvious scam claim on the basis that some guy said so, you would most likely conclude that that person is being unreasonable by being convinced on such evidence.

When you get to extreme ends of the spectrum, it's no longer subjective whether one should or should not be convinced by a given set of evidence, in that there are clear epistemic issues with picking one or the other option at that point. Religions all fall into the latter extreme, where if they convince someone, they are doing so on insufficient evidence that followers would never accept for other claims, or even other claims within the same type.