That isn’t true. ILS is a concept that can be readily demonstrated in simulations, by math, geometrically/visually, and also demonstrated in populations everyone agrees shares common ancestors. There is no reasons that creationists can’t come to understand it.
They might still say this isn’t the right explanation from ILS with humans and the great apes, but they might stop making absurd arguments like this one from Doug Axe:
Well, the recent publication of the gorilla genome sequence shows that the expected pattern just isn’t there. Instead of a nested hierarchy of similarities, we see something more like a mosaic. According to a recent report , “In 30% of the genome, gorilla is closer to human or chimpanzee than the latter are to each other…” // That’s sufficiently difficult to square with Darwin’s tree that it ought to bring the whole theory into question.
The Gorilla Who Broke the Tree - Biologic Institute
This is a totally indefensible line of reasoning. We expect imperfect trees in common descent, so ILS is not evidence against CD. Why then would anyone present it as evidence? The clue is in the quote. Axe is arguing against “Darwin”, who knew nothing of genetics, let alone population genetics. The poor guy is dead too, and can’t defend himself.
At some point, I hope that Axe catches up what we know about population genetics. If his other arguments against evolution are as strong as he thinks they are, he should have no need for obviously invalid arguments like this, right?
Don’t forget about the gorrilla in the room. It is a good read in itself: