>> So much of so many things is subjective.

Yes, but even subjective judgements are invalid if they're not based on objective differences.

If you reliably prefer white wines in blind tastings and I reliably prefer reds, that's valid. But if we both claim a preference but can't actually identify which is which, our preferences themselves are invalid.

Or at least, we've learned that our true preference is "I like the experience of tasting a wine that I have seen is X color."

Perhaps the truth is sometimes "I enjoy consuming something that I have been told is expensive." It would at least be enlightening to know that about ourselves.