Since rights, liberties, and laws are all based on personal values, which are ultimately just opinions, there is no factual basis for any of those things. They all stem from emotions. I have empathy. Whenever I do something to someone else, I put myself in their shoes and ask myself, "How would I like to be treated that way?" If the answer is, "I wouldn't like it" then I don't do it. At some point, we might disagree because we don't all have the same opinions and there's nothing we can do other than agree to disagree when our beliefs can coexist or commit violence against each other when our beliefs cannot coexist. There's no shortcut, I'm afraid.
Genocide is a direct refutation of utilitarianism. I'm sorry if you were offended. I really respect you because, even though we disagree, you are respectful. So, I regret offending you. However, my point was only that it doesn't matter how many people want something, if it's wrong, it's wrong.
The problem with your "How would I like to be treated that way?" test is that you ignore the fact that your beliefs damage other people and only look at your own loss of freedom. People don't like being damaged - its not cruel or oppressive for them to say "Stop. I like movies, games and Coca-Cola and if you don't, then simply abstain from having them instead of undermining the legal basis of my having these good things."