Not every atheist thinks God is evil.
Some just think he doesn't exist. I remember a youtuber I watched as a kid, Hemant Mehta, said that he wanted to believe and that if God ever revealed himself to him he would convert.
I think there's a big difference between those who claim that God is evil and lie about what happens in the Bible to justify doing so, and those who deny evidence of him.
Namely, in that if you would call God evil, even if you did good works and gained faith in him, you wouldn't be saved anyway.
How could such an arrogant person do good works anyway? So egotistical as to call a God they don't believe exists evil but too cowardly to call his followers evil.
It's always God they call evil. Not Jesus because all know deep down that he was perfect. Not even Christians. I never hear anyone saying Christians are evil, not even Satanists or Pagans. It's always "God", or "Christianity". Strange that.