This is just how science works: we find evidence for some things, and we don't have evidence for others, so the things we can explain is limited to what we can back up. For example, we don't know why people yawn but that doesn't mean that we can't explain in detail how sedatives work.

But we also can’t explain in detail how sedatives work... We have no idea whatsoever how most classes of sleeping meds function.

We have a fairly good idea how most sedatives work and which receptors they bind to. But even when we don't, I am not sure what your point is: even when we know some things there are still things we can't explain yet…which was basically what I said?

I expect you're uninformed but I don't know enough to prove it. Either way, I'm annoyed that you've been downvoted without a single reply. I'd like to know if/why you're actually wrong.

It's true that physics can't explain galaxy rotation (speaking as someone who recently taught elementary cosmology at a good university). I don't know whether that has much to do with the big bang though. I expect the downvotes are for non sequitur.

You are essentially correct - popular scientism outlets do not have an appropriate degree of humility when reporting on things like this. However, the physicists themselves tend to have a good understanding of the caveats and context of their predictions, even if this doesn’t generally end up getting communicated to consumers.