The law of mutual exclusivity is a human construct. Wouldn't God transcend those constructs?
One blind man feels the elephant's trunk and says, "It's a snake".
Another feels its tusk and says, "It's a spear."
Another feels its tail and says, "It's a rope". You get the picture.
The point this story tries to make is that all the world religions are only getting a part of the picture of the true deity, and that no one has the privileged position of seeing the entirety of God. So what we think are mutually exclusive descriptions of God -- it turns out that they are not really mutually exclusive because no one can see the entire picture. I think that's a helpful analogy that show the limitations of human knowledge.
It's important to note that Christianity is not claiming that we human beings can understand God fully. However, there is something ironic about this parable. Because this story is claiming that there is someone who can see the entire picture! Who is that? It's the storyteller! In other words, the pantheist is the one who sees the whole elephant! Maybe not exhaustively, but at least the pantheist is claiming that he's in a more privileged position to have a better understanding of God than others, so he alone has the special overall knowledge that these poor blind men do not.
Do you see the point? By claiming that all religions are basically the same, that person is saying that when the different religious people, like Christians, Muslims and Buddhists, claim that their description of God is different from each other, well... they are mistaken. Only the pantheist picture is correct!
So it turns out when a person claims that God transcends law of mutual exclusivity, and therefore all religions are correct, that claim itself assumes mutual exclusivity! It's a self-contradiction.
To illustrate, let's imagine that I have a conversation with someone who tells me:
A: "Hey. It might seem like religions are different, but God transcends logic. All religious beliefs are correct."
B: "Oh.. so Christianity is correct?"
A: "Yes. All religions are correct."
B: "But Christians believe that the Christian God is quite different from the other gods that people serve. Christianity calls that idolatry, and that's a sin."
A: "No, that's not correct. Christianity is wrong if it claims that."
B: "Oh. But I thought Christianity is correct."
I hope you can see the self-contradiction here.