There is a common claim in amateur philosophy that all religions are basically the same. A similar claim is that Muslims worship the same God as Christians. A simple refutation of this claim is to point to a picture of Jesus and ask "is this your God?" If you do this, a significant portion of religions will answer in the negative. Even many pseudo-Christian religions deny the doctrine of the Trinity, so you'll find that actually, even some people who say they are Christians will not say Jesus is their God.
This fact alone is enough to say that Christianity is almost unique among world religions. Compared to the number of religions out there, there are almost no religions that acknowledge the divinity of Jesus. But even once we have eliminated the majority, you still have Christianity and a few pseudo-Christian religions. What do we do with those? This is where I reveal the significance of the picture. The picture itself is not a god, but it represents a real historical event upon which the Christian faith is based. If a man came out today claiming to be Jesus, developed a cult following, got himself crucified between two thieves and his followers called themselves Christians, they still wouldn't be able to honestly point to the picture and say "yes, that is my God" because their "Christian" faith is based on a completely different figure. A fake. A reimagining. The same would be true if this fake Jesus never really existed, but was believed in none the less.
What does this have to do with anything? Well, by definition, changing any fundamental attribute of a being makes them a different being. Just as a new Jesus today would not be the Jesus, so also is this true of fake Jesuses of fiction. So, you ask a few more fundamental questions. Did Jesus have real flesh both before and after His death and resurrection? Is Jesus the one and only mediator between God and man? Did Jesus fulfill the Old Testament law, rendering civil and ceremonial laws obsolete? Did Jesus die for all sinners? Was Jesus' death fully sufficient so that we don't have to work for salvation? If the answer to any of those questions is no, those who originally said "that is my God" must now admit "that is not my God."
Therefore, not only is it illogical to state that all religions are the same, we find that actually, not even all religions that claim to be Christianity are the same. It violates the basic logical law of identity to claim otherwise.