Usually I should not care whether you like apples or not. The taste for apples is your personal preference. But some people have nosy preferences. They would like me to eat apples to improve my health EVEN if I do not like apples.
Nosy preferences may be preferences that run against other people's preferences that have consequences with an unacceptable social cost. If not eating apples were to have a high social cost that resulted in an increased burden on the healthcare system and hence an increase in taxation, a nosy preference for others to eat apples can also be a self-regarding preference. I would venture to say that any preference of mine that is not universally shared, and whose non-preference and non-satisfaction by others places a cost on me that I don't want to accept, would have to be or entail a nosy preference, on pain of my being irrational. Of course not all preferences, nosy or otherwise, can be accommodated by public policy; it's a problem for decision theory.
In a democratic system if a fair amount of people have a nosy preference about a certain topic and they are intent about that preference while the opposition of that preference is weak two solutions are apllicable: i) giving up democracy for a degree that only protects individuals' liberties or ii) building up active oppositions, liberal social movements. Usually constitutional law solves the problem by limiting the democracy.