The whole concept of "taste" being important bothers me, frankly. It's often implied that it's some objective thing, when it's really purely subjective. I accept that it's important socially to present as someone "with good taste", but I genuinely feel any effort in this direction is really just a huge waste of time.

Why not just enjoy the things you enjoy? And if the things you enjoy drift over time as you experience more and notice more patterns then fine, but this does not mean the new enjoyable thing is in any objective sense better then the old.

Finally, I'm completely fine with a website that looks "exactly like every other website".

Is it subjective to say that Apple had more taste in producing the Mac OS than Microsoft when they produced Windows XP?

Its not as subjective.