Yes they do? Twitter does a good job on finding out where people work, informing their employers about their social media presence, and getting them fired. When they're the ones who should in theory, support such a practice.
The only people you can't "get" are media people. But the left has its side because everyone fucking hates media people. You go down the street and ask if you get political opinions from fucking MSNBC, youtube commentators, or fucking Markplier, or this asshole, and their going to spit take in your face.
Most people don't have time for that.
The idea that the "left is losing" is undialectical as hell, the material conditions that Capitalism is creating is, I would say, nurturing coming leftist insurrection and Capitalism can't do much to stop it because it's reaching the end of its reign. The rate of profit is in freefall and has been for years, the climate is only getting worse to make the market far more unstable, as well as people's lives. This all neccistates violence, and the world's western governments can only take advantage of this by blaming the other for so long before people realize the only people with resources left
are
them.
The capitalists. The wealthiest.
This is what has lead all revolutionary struggle in the past and it shall do it again.
These people can fucking have pewdiepie or whoever fucking Let's Player influencing their politics all they want. In the end, it still won't save Capitalism. It still won't save the rich. No kingdom lasts forever, and this kingdom is on its 21st century death knell. It won't happen this year, or even this decade. But it will happen this century.
I don't think, in the grand scheme of things, attention whores who get paid by google are going to do anything to stop the longest struggle in human history. Between freedom and feudalism, capitalism and communism, wealth vs labor, men vs the systems they create to take advantage of other men.
Thinking youtube will stop anything is very narrow minded. We are accelerating towards a point in which heads will roll, and we've long passed the point of no return.