College and university is a strange time. For many, it is a golden time they look back on happily for decades after. For others, it's confusing and full of rejection. Part of the difference is just the luck of who you bump into. I was rejected by many people during that time, but I met others who have been dear to me for over 40 years and still are. I saw plenty of people try to make those kind of connections and never quite get there.
Let's start with this: You cannot "confront" people that it is unfair to ostracize you. You can ask them nicely to include you. You can change the way you behave around them to make it more likely they can include you. Or you can look for folks a little further afield who will include you.
For example, if they have a sport they all play together that they all excel at, you can't demand they let you play too when you barely know the rules. These things are not done on the basis of fairness. They are done on the basis of having a good team or winning lots of games.
What can you do? You could ask if you could come and watch them, to learn more about it, assuming you would enjoy that. You could invite them to join you in something you're doing. You could try to learn a hobby, perhaps by asking one of them to help you learn it. ("I always wanted to knit; if I get started would you help me some times?") Or you could seek out other people at the college who like what you like (particular music, games, books, etc) and spend your time with them instead of the people in your class.
Investing brain cycles in understanding why people reject you is rarely useful. The wording you're using, even less so. It may well be that they are rejecting you because you are not good at sport X and they are good at it. While the reason you're not good at sport X could very well be your parents' choices, not one person is saying "ew, don't invite Germania, their parents never took them to sports." Not one. If you are being rejected for not being good at sport X either get better at sport X or find a way to be included without being good at sport X -- the suggestions in my fourth paragraph. But attributing your current misery to a past unchangeable decision by someone else will not lead you forward to a happier place.