Without asking "why is the speed of light constant", you wouldn't discover the reason. The reason is that space is not just space, but space-time. There is not

Without asking "why is the speed of light constant", you wouldn't discover the reason. The reason is that space is not just space, but space-time. There is not always as discoverable reason behind a physical phenomenon, but sometimes there is. Not asking why altogether isn't a good approach in my view. But I understand your perspective.