Thats not dispositive of the fact there is very much rhythmic/aural entrainment.

As I mentioned, I didn't find any official sources for that. I won't claim they don't exist, but the fact that research on that topic is harder to find does not work in favor of its validity.

I like it and I think it is relaxing.

I think this is all that you should be concerned about. If you like it, there's no harm in enjoying it as much as you like. Sometimes the mystery is the magic, y'know?