It’s almost like it’s a multi dimension spectrum with axis like left<>right, conservatist<>progressive, liberalism<>socialism and more… but simply “the left” and “the right” are popular (but problematic) terms that everyone recognises but everyone has their own interpretation of. However, if you want to be more accurate in you political discussions, you’ll have to write full page monologues and that is often not the way of the Internet. It will more often fall on deaf ears than not. And therefor the louder voices with the simpler terms get a bigger audience and reach eventhough the things they are saying might not be as good.