Because they have the same problems of the traditional press.
They are filled with sophistry, opinion, and filler. The facts are sprinkled here and there to maintain a façade of legitimacy.
The press has diluted the products so much, that they have lost their mandates, and most online news outfits (The Intercept being a noted exception as is WikiLeaks), roared on to the scene with a model that was all filler and sophistry because they were going to wow the crowds with attitude.
Attitude doesn't cut it. Attitude is cheap and it is usually a feint to disguise the fact that you're not all that. It is a form of misdirection, and no matter how sassy you are, your product speaks louder than your sass.
The advertising model is being blamed, but really, if the crowds were there, advertisers wouldn't even care. They would not turn up their nose at the rush. The Drudge Report could not be simpler, but its elegance in presentation ensures that people will come frequently to get a pulse of what's going down in the world. No one in the news world has managed to clue in to the its structure's significance.
So it is not about the finding model. It is about trying to stretch the tiny attention spans of audiences who are trained to point and click by the way tablets and smartphones have been set-up.
People come to a site, determine tl;dr, and then leave. No investment, and why not?
Because the Internet is all about fragmentation.
It is about reacting, not reflecting.
That is the problem that has to be addressed just as news producers have to relearn how to understand their atom of their existence: the fact.
They have to understand reality and truth, and Buzzfeed and Mashable never got any of it.
The model of journalism needs to change. The new media and the old are both equally clueless that their structure is flawed and unworkable.
Figure out the news part, and everything else begins to fall into place.