When people discuss religion in general they sometimes speak of theism. [View all]
When things get down to brass tacks, though, religious beliefs are non-inclusive. Most religions take themselves to be the only correct religion. The other religions are wrong. It doesn't really matter which religion one follows. That one is the correct one. The others are in error.
And that goes right down to the denomination level. Denominations form after disputes with a parent denomination. There are protestant denominations that believe that Catholicism, for example, is not true Christianity. In fact, some think no branch of Christianity is correct except their own denomination.
And then, Islam, which worships the same basic deity, is either horrible or the only true religion, depending on whether you are Muslim or not a Muslim.
How does any of that make sense? Where is the logic? If an all-powerful, all-knowing deity cannot get its followers to agree, then one has to wonder about those attributes, I'd think. Instead we have warfare and longstanding hatreds. None of that makes any sense at all.
Still, all of the theistic religions think that atheists are wrong. In that, they have common ground. Atheists reciprocate.