YouTube is just one of many content platforms. They happen to censor more material than others because it’s typically kept mainstream and accessible to all audiences.
Political censorship definitely happens on their platform. I listen to a pro wrestling podcast that often contains a lot of comical ranting on whatever Donald Trump, politicians and the republican voters have done that week - the version on YouTube is often 20-30mins shorter than the full episode on the podcast apps (Spotify etc) because they cut all the political material out to avoid running into issues.