Indeed. We have had message boards, subreddits, newspapers, TV news shows, radio shows, etc. dedicated to (or at least slanted towards) specific policial views

Indeed. We have had message boards, subreddits, newspapers, TV news shows, radio shows, etc. dedicated to (or at least slanted towards) specific policial views for quite some time. Possibly centuries in the case of pamphlets and newspapers, often printed with an explicitly partisan point of view in ye olde times.