Atheism as a philosophy and personal life style is the acceptance of the self-assembling universe and the nothingness at the end of life. So on that basis it is not a religion.
However, atheism as practiced by many of its advocates (not all by any means) is a religion because it actively denies the right of other religions to practice. War Memorials having a cross, city seals having a cross, cities having names derived from a belief, all of these have been taken under fire by atheist-espousing organizations. In this case it is a religion.
As you pointed out a belief in atheism ( or atheist worldview) is not neutral in content or consequences.
The most profound influence of atheism is in our nation’s socialist-entitlement schools! This influence is NOT neutral in content or consequences for the child or our nation.
No school can be religiously neutral because all schools must choose a worldview that is either godless or God-centered. Neither of these worldviews is neutral. Placing citizens under police threat to pay for the establishment of a religious worldview ( godless or God-centered) that abhorent to their conscience is an abomination.
Personally, I consider it child abuse to force any child from a God-centered home into a godless school where they must think and reason godlessly just to cooperate in the classroom It is also child abuse to subject a child from an atheist’s home into a God-centered classroom.
Fundamentally, government socialist-entitlement schooling is a freedom of conscience and First Amendment abuse.