Are you a secularist by the mere fact that you are an atheist?
What is an antitheist? Is that like the militant wing of the atheism?
I'm an anti-theist. My "belief" is that religion is a virus that should be eradicated. Why? For the simple fact it gives people reasons not to get along. It breeds fear, hatred and content for things people don't understand. Almost every religion is also a scapegoat system. Good=God did it. Bad=satan did it. Truth=you made a choice and did it yourself. Not God, not Satan, you and only you.