American leftists have always shared the same view as you. The left-leaning news networks are simply straight news, unbiased, doing it right... and everything their ideological opponents watch is far-right propaganda.
As a leftist who feels the Democratic party is a center-right party, networks like CNN and MSNBC come across as deeply biased but not particularly "left". Maybe Liberal, but certainly not "Left".
Right and left have been rendered almost meaningless, especially in this context.
What is called "left" these days is more, "that which conforms to Democrat narratives" and lately quite illiberal, while pretty much anything else is called "right" or "far-right" even when it's attacking corporations or the military-industrial complex.
This is not my view at all. News can be biased/sensationalized, even when it's neither left nor right. CNN and MSNBC are (as far as I can tell) the tv equivalent of clickbait. They are just (compared to the extremes of FOX) centrist about it. The only thing I would call straight news in the US would be PBS.