You could go out on the street; but finding and then having someone say something on camera is -very- different to finding and showing a tweet. I feel pretty confident in saying that a lot of people tweet stuff they’d never say live in front of a camera.
Hence the argued bad practice of presenting tweets on news shows as well thought through and relevant opinions.
Why would they be irrelevant? It is opinion that people think. It migh be wrong, but they still vote on that, choose schools on that, make decisions and judgements about real life people around them etc.
"People are clamouring for more of X in Y" and then they show three tweets.
When really maybe nobody cares. Or maybe they care in the other direction entirely.
Secondly, even if they're real, how do you know that they're representative of anything? Twitter is global. US politics, for example, could be followed by Afghan kids. Why would US news care about likes from people half a world away?
Thirdly, there's a lot of dumb people around. There's several reasons old media is tightly curated, and not all of them are related to making money or to censorship. A good chunk of it is to not show (just) garbage.
Huge chunk of "old media" is garbage too, just with little bit better grammar. One thing that curation of old media was bubble too. It made people convinced that "nobody think that" while quite a lot of people actually think that. I don't mean outright censorship here, but the range of arguments and opinions being expressed was much smaller.
To some extend, I understand how ideologies can be dangerous and how their promotion in media threatens us. But you don't seem to object on the "this person is promoting ideology that leads to less freedom" grounds. You seem to object on the "these people should not matter" grounds.
Lastly, it US cared more about what Afghan kids like, US would be less cool about killing them and about destabilizing whole regions of world.
You can still get that while citing twitter, but you can also get those 1:1000 opinions that were impossible to find before, and make them look unreasonably common.
Mother said "if you can't say something nice don't say anything" maybe we need to move to "if you can't say things that are novel and well found then leave it be"?