Because they haven't learned any lessons from the media's prime-mover influence in the creation of Donald Trump - a person they highlighted and platformed for the same reason - as a viable and then successful presidential candidate.
The American news media created Donald Trump, but not on purpose. Not because the media, at large, actually wanted or ever thought he could win. People like this lady and Donald Trump are picked up by the media because the media sees them as a political "Honey Boo Boo", a person that the public is supposed to listen to and watch and be entertained; to laugh at how stupid, ridiculous, backwards, and outrageous they are. Even while making fun of him, they carried every single one of Trump's campaign speeches live, preempting actual news, because people WANTED to see the spectacle - even people who hated what he was saying were addicted to watching him so they could laugh at the next fact he got wrong or made up, or the next time he contradicted himself.
The media has never understood that even their pointing and laughing is providing free campaign services for people like Trump. They've convinced themselves that some middle-America grassroots social uprising made Trump's success inevitable and they've really pushed that angle in all their post-Trump editorializing, and that's let them for the most part kind of whistle past the graveyard about their own culpability.
And that's not just my opinion. Do you remember Ron Paul's pathetic campaigns during the Obama-time and pre-? Ron Paul supporters were absofreakinglutely nuts. They were making literal actual gold coins with his face on them. They were doing all the internet memes about him. But he failed utterly because he just never got coverage - most of the people in the US prolly didn't even realize he was running. Ron Paul is what happens when the media doesn't platform a Donald Trump.