If you have ever been a member of a group you know that each group has a certain list of things you must believe in. Sure, many claim that your total adherence is not required, however, your success within the group depends how well you do.
Membership or non-membership in a group does not change the fact that you are an atheist. Atheist means only that you do not believe in any gods. It does not mean that you must support every “liberal” or “leftist” ideal or belief. In fact it does not mean that you have to support anything other than atheism.
Groups of atheists who do support everything put in front of the group will no doubt label you with degrading names. They will label you a bigot, troll, racist, sexist, etc… and you aren’t any of those things. You simply have your own mind and will only support that which you feel comfortable with supporting. Nothing is required of you beyond the simple support to further the acceptance of atheism. Even that is not a requirement, you can be an atheist by your lonesome.
By what authority do I make these statements. I am a human, what do I have to be? How else does one resist being controlled by others?