An atheist basically doesn't believe in god or a deity. They can sometimes even claim "spirituality" for whatever reason.

An anti-theist is arguing that the concept of worshiping a god is actually wrong. You're not just saying there isn't a god, you're saying that people should actively stop worshiping a god.

Now, there's plenty of Communist and Marxist Anti-Theists, but I still see Leftism operating as an effective religion, even down to the Marxist argument that it's an "opiate of the masses". Frankly, I think that concept fits social justice causes very well, and the deification of George Floyd makes me argue that they aren't in opposition to religion, they are creating their own.

I take my position more for a Nietzschean approach: "God is dead, and it is we whom have killed him." If you kill God, you've got to take responsibility for that. All the utility of gods and religions, now has to come from something else. Yes, it's true that my life would be easier if I had more formal traditions and ethics to unthinkingly fall back on, but because the very notion of God is effectively dead to me, it means I had to figure it all out, and hilariously came to the same conclusions as a lot of protestants would, but from (what I would argue) are far more well reasoned and well founded foundations than a simple reliance on tradition, and hopefully a book.

My problem with that reliance on religion is that we have clearly seen it bastardized for evil, and even for Leftism, using the trust and faith of those institutions as a weapon to corrupt and destroy the lives of the innocent. Fundamentally, my argument is that churches can't be trusted with the concept of God (that which is the objective immortal truth, and the path of righteousness). The worst form of the church is when weak-willed people pass off the responsibility of interrogating their own beliefs to the authority of the church, and are headed like lemmings into evil. I refer to these people as "Jesus Take The Wheel" Christians.

I have far more in common with protestants who understand their lives as a religious journey to discover how God "reveals himself" to them through their lives on an individual basis. This is a perspective that at least operates off of the premise of responsibility to find God/Truth in things.

I prefer if they didn't ascribe all of the ways of the universe to, what is ostensibly, a magical figure. Magical Thinking must be avoided in order to live in truth, but concept of God itself is Magical Thinking.