Most atheists only know about one religion well: the one they disowned. But they tend to make careless assumptions about the rest when they "oppose all religions equally". And since they are quite uninformed about other religions, they easily fall prey to bigoted narratives.
Even the theists who criticise organised religion for its faults often make generic assumptions in their arguments based on their own experience. They fail to acknowledge the diversity in belief systems and sees every faith through the same lens, again aiding bigoted narratives.
(since such large number of people seem to have misread the above for various other points, just FYI - I'm an atheist myself, if that can help with your comprehension)
