It hasn't anything to do with Boycotting. It is just that some advertisers don't wanna pay to have their adverts shown next to those gross discussions.
This is probably the most important point to consider about this situation.
This. I simply cannot have my ads on this type of site. So I will seek and pay for ad networks that guarantee that my ads don't appear there. This is simply the free market.
So you just pay people you fundamentally disagree with? Not every boycott is undertaken to change things, they can also be done simply to have nothing to do with what the target is doing.
I don't think anyone is under the illusion that Breitbart can be boycotted or shamed. The market they cater to lives in a pretty air-tight bubble, the same bubble which sustains Fox News/Drudge Report/Rush Limbaugh etc....
Clickbait becomes pointless if all the ad networks ban them
You say this like the left doesn't have its own in the NYT, CNN, ABC, NBC, Huff, Salon, etc... that's much more of an bubbled echo chamber. At least on the right they get bombarded with MSM daily... they just know its straight up corrupt.
The left has its own biases, but to equate it with the Fox News/Breitbart bubble is dishonest. To take science as an example, the left has its own set of denialists (ex: anti-vaccers, anti-GMO), but the left has plenty of people who push back against such science denialism. The Fox News/Breitbart bubble doesn't have any such checking mechanism. There's a reason why creationism is popular in the US.
What do you suggest instead?
It's possible that it actually has worked, and things would be even worse without.
It's a reference to Trump's presidency, and how some people think it was brought on by left-leaning journalists.
it maybe be a necessary if not sufficient condition