NPR is not considered centrist, but left-leaning.
When I check logged out I get CNN and Fox side by side, along with a lot of non-political basketball and Mr. Beast type stuff. Content probably varies on your IP address.
But calling everything disliked "extremist" is counterproductive and is itself an Overton window shift.
For example, does anyone really believe that no abortions, no exceptions, even in the case of rape of a minor is not extreme? We have 15 states right now in the US where that is the case and a large cadre of gop politicians that believe that is how it should be. And not only are those states enforcing this ban, some are going so far as to try to go after people who leave the state to get in many cases, life saving abortions.
I also think that unlimited abortion for any reason up until the moment of birth is an extreme position. Guess how many states in the US that is legal? It's zero.