It is a line of BS pushed by theists, whose next move is usually to try to change the burden of proof from, prove there is a god, to, prove there is no god. They think that if they can force an acceptance of atheism/agnostic as a religion, then you have to prove your faith in your religion just as much as they do.
Certainly some individuals present their atheistic religious opinions in a rigid and religious-like way, and can not tolerate any other view.
Whether a person is a robot-like Bible thumper or a raging, robot-like atheist doesn’t matter—they are both blind and the difference between them is only one of labeling.
it is only looked at as a religion by people who cannot comprehend not believing in a religion. but actually atheism isn't the absense of a religion. it's the absence of a deity. there are plenty of people who don't belong to a named religion but still believe in some kind of deity. i like this old chestnut: atheism is a religion the way bald is a hair color.
Religion says 'believe it'. Science says 'prove it'. Atheism is indeed another form of religion. The atheist says 'there is no god, no great pumpkin, no great bunny rabbit, no way, no how!'. Yet, they cannot prove, or disprove their assertion. They just expect you to believe it. That's why I choose to be agnostic. Agnosticism is the scientific approach.
In some contexts it’s justified, as an expedient. White isn’t a color, but if you’re trying to register your white car with the state and they ask what color it is, you say without hesitation, white. You don’t stand there and argue that your car has no color.
That's theist's trying to bring you down to their level in order to assert that your belief is no more valid than theirs. Many can't deal with ambiguity and don't see that it's not necessary for everyone to "pitch in" with some particular doctrine. Others are comfortable with Agnostics, because that position doesn't pose a great threat to their's, unlike the concept of Atheism, which directly implies that they are wrong.