Excellent point Joseph.
What you are saying is that people feel like their taste is something they were born with, while opinions they get and change through life.
This is obviously silly of "them," as we develop and change our tastes just as much as our opinions. Our senses can be educated and change. Even our taste in the sense of food.
I must admit I don't always follow the kitchen discussions here, but I remember a conversation (perhaps offline) where the topic arose of how foods you crave are actually usually foods you are allergic to. In that sense one can say our tastes are very physical and we might have been born with them. Still, even with food, I think that's hardly the case. (For example, I didn't appreciate good chocolate until a friend bought me a big box of it and after eating 2-3 pieces a day for a while did I start to appreciate its taste instead of the stronger simpler taste of cheap chocolate, which I also still like.) In another discussion it was mentioned how foods we like and need might be connected to our blood type, etc.
So yes, there might be an inherent taste with regards food, though still not completely, but that's also true about our opinions, or at least connected.
In fact, it's hard to even distinguish between our tastes and our opinions. Liking a movie is an opinion or a taste?
Still, I think people tastes often reveal more about themselves than their opinions. I remember reading somewhere Pauline Kael, the film critic, how she once went out with a guy, and when he told her he liked some movie she immediately stopped dating him. Even with my own friends, if there is a movie I especially like and they don't, I feel it reveals something about them; something more that what opinions reveal. Maybe because people are more careful in what opinions they voice but are unaware of what their tastes reveal.
Found the Kitchen discussions mentioning your blood type influences what foods are good for you:
post