First step was when internet went mainstream and news papers had to compete with news online. Things got a lot more attention grabbing. Or at least more articles got clickbaity. Then came from social media, who loved to use emotions to drive engagement so you got a lot of articles with emotional attention grabbing language. Meanwhile there is a large wave of consolidation where small media companies are bought up by bigger ones, usually with political leanings, that then start pushing a message, an ideology held by a small group. All together you now have a small group spouting their opining everywhere with very attention grabbing emotional laden headlines.

Because facts don't matter anymore and news outlets noticed it's easier to get clicks. If necessary, sock puppet the handful of enraged Twitter user yourself, boom story.