Several times, I've seen 'why' questions dismissed unfairly when a better answer could be given, because of a kneejerk reaction that a 'why' question can never have an answer, because physics is built to model reality. Below are some examples.
- A questions about Ito and Stratonovich calculus, asking why we choose one over the other in physics. There are lots of disparaging comments about how such a question is meaningless.
- A really deep question about QCD bound states, which received an answer saying "physics does not answer why questions".
- A question about SU(4) symmetry, which is being received poorly.
- A question about the spin of fundamental particles, which I can totally imagine being received poorly today, but happened to get a fantastic answer when it was asked.
As shown by the last example, there are lots of good possible answers to a 'why X' question.
- You can show that if X weren't true, there would be some internal contradiction, or you would lose some important, more fundamental principle.
- You can show by analogy with simpler theories (e.g. classical limit) that X makes sense. Or, if there are deeper theories, you can derive X from one of them.
- You can use anthropics, i.e. argue that something would go horribly wrong with the universe if X weren't true.
None of these things answer "why" in the philosophical sense, but they do answer it perfectly well in the physical sense. Can we just assume that question posters mean the latter, instead of ridiculing them for possibly meaning the former?