A person whose spent thousands of hours making and consuming music is going to notice and value different things than someone who just listens to whatever is on the radio.

A person whose driven hundreds of cars probably has a way better idea about what they like and what they don't like in a car than someone whose driven 3.

That's what having a "developed taste" means. Yeah it's all opinions, but you can't even know what your opinion is of something unless you try it, and you can't develop an in-depth opinion of something unless you've tried a whole bunch of similar somethings.

That doesn't mean you need to do that with everything of course. Not everyone needs to cultivate an appreciation for everything, I don't know or care what good beef Wellington is like for example, but I'm also not going to get pissy with people purely because they have different interests than me.