They realize it, they just don't want it to exist, and have a vested interest in muddying the waters of discourse such that most people remain unaware of it, or mistrust it in principle. For a few years they've been actively campaigning to have protections like Section 230 repealed and have all social media platforms (with some arbitrary number of accounts) be taken over and regulated as utilities by the government.
I disagree: I think people genuinely do believe their own opinions, and politicians are also human....thus delusional, and corrupt, necessarily. But they ain't stupid (or at least their PR folks aren't): a well done (mis)representation of reality is well known to be more than adequate to fool most people most of the time, and misrepresenting reality is at the core of "successful" (depending on your perspective, I'm talking electoral and financial success) politics.