The idea that rights are inalienable is a fundamental moral principle of every modern free society. People can violate your rights. That doesn't mean that your rights go away. If someone steals your laptop, you do not lose your right to that property. If the people around you form a mob and burn down your house, they haven't revoked your rights, they have committed a moral crime against you — they've violated your rights.

I wonder if your question is facetious or ignorant, but I will answer you as though it is earnest: I get it from great thinkers such as John Locke, George Mason, and Thomas Jefferson. To the extent that you support any kind of civilizational progress, you have these thinkers and their ideas to thank.