It doesn't 'personalize' it for you though, you do that for yourself
All the default sorting algorithms do is sort by basic global metrics like time and activity - anything else is done by the user (blocking, subscribing, ect) and the instance (federation or banning).
People misunderstand just how broad a term 'algorithm' actually is.
Liberals and progressives staying home wouldn't matter if the democratic party appealed to the working class as a whole instead.