One of the most bizarre arguments I have ever heard in ethics is whether or not people can choose to be gay or not. The idea is, if being gay is genetically predetermined, it's not their fault, therefore you can't prosecute them for something they have no control over.
Since when did anyone get to choose what makes them happy? Can you choose to like strawberries? Can you choose to enjoy the smell of dandelions? At best, you can subject yourself to something over and over and over again and enjoy it as a sort of acquired taste, but this doesn't always work, and the fact remains that you are still predisposed to enjoying certain experiences. Unless we make a concentrated effort to change our preferences, all enjoyable sensory experiences occur without our consent. We are not in charge of what combination of neural impulses our brain happens to find enjoyable. All we can do is slowly influence those preferences, and even then, only sometimes.
This concept of people choosing what they enjoy seems to have infected society, and is often at the root of much bizarre and often unfair prosecution. If we assume that people cannot significantly change the preferences they were dealt by life, either as a result of genetic or environmental influences, a host of moral issues become apparent.
Gender roles stop making sense. In fact, prosecuting anyone on the LGTB spectrum immediately becomes invalid. Attacking anyone's sexual preferences, provided they are harmless, becomes unacceptable. Trying to attack anyone's artistic or musical preferences becomes difficult, at best. We know for a fact that someone's culinary preferences are influenced by the genetic distribution of taste buds in their mouth. It's even hard to properly critique someone's fashion choices if they happened to despise denim or some other fabric.
As far as I'm concerned, the answer to the question "why would someone like [x]" is always "because their brain is wired in a way that enjoys it." Humans are, at a fundamental level, sensory processing machines that accidentally achieved self-awareness. We enjoy something because we are programmed to enjoy it. To insult what kinds of sensory input someone enjoys simply because they do not match up with your own is laughably juvenile. The only time this kind of critique is valid is when someone's preferences cause harm to another person. We all have our own unique ways of processing sensory input, and so we will naturally enjoy different things, through no fault of our own. Sometimes, with a substantial amount of effort, we can slowly change some of those preferences, but most of the time, we're stuck with whatever we were born with (or whatever environmental factors shaped our perception in our childhood).
Instead of accusing someone of liking something you don't approve of, maybe next time you should try to understand why they like it, instead. Maybe you'll find a new friend.