Well, she's got some lady balls to go after the largest disseminators of news (WaPo is owned by Bezos after all) right at the start of her campaign.
Frankly I disagree with her, not out of any love for Facebook or Twitter or Amazon, but really that issues that exist with these platforms is a symptom of a deeper cultural illness that is exposed by but not caused by the platforms themselves.
Breaking up these companies is heavy handed, with unpredictable results, and really just pushes the problem elsewhere (Materialism, Emotional Thinking, Tribalism, 140 Character Deep Thoughts).
WaPo isn't part of Amazon so the first part is just nonsense. And Bezos trying to force WaPo to target her would backfire spectacularly and actually legitimize her saying something needs to be done about them.
The thing is, she's not wrong that there's anti-competitive issues at play. If you actually look at what she's saying, she pointing to legitimate anti-competitive behavior (i.e. working to control the marketplace that you're already fairly dominant in, and then using that to gain unfair advantage, or ). Frankly, I don't know how the hell Apple was able to get away with some of the stuff they've done (like forcing others to use the Safari rendering engine, that's worse than what Microsoft did with IE, and Apple was already pretty much doing what got Microsoft in trouble, and then took it to a new level; and their shenanigans in trying to deal with Amazon's anti-competitive behavior by colluding to fix e-book prices).
I don't really agree with her in that I think there are other markets that require attention as they are bigger issues (that actually help those companies in the practices she talks about), and I do think there's definite potential downsides to breaking them up, so I'd prefer other courses of action, but I think there's definite things about them that warrant scrutiny (a major one is the lack of accountability for not taking people's privacy and data seriously).
There's plenty of legitimate stuff to go after these major corporations in general on too. Like trying to force arbitration on various issues (both as consumers and employees). And so I think we should start with that stuff. And like with Amazon (who has started doing stuff like Wal-Mart, underpaying employees such that they end up dependent on social programs) getting special tax breaks (they're hardly the only one though). Although I'm not sure there's any reason we couldn't also look into other aspects at the same time. There's definitely some issues related to marketplaces that needs looked into (app stores like Apple, Google/Android, Microsoft, and Steam - Steam tried to fight against abiding by laws, like offering refunds for a long time).
This is very different from what conservatives have been pissing and moaning and calling for something to be done about them. Well for the most part (there's a jackass from Missouri that is using him going after them in some legit manners to build up that he's tough on this stuff for political clout when I think its more that he's just trying to harm them any way he can and they just happen to give him an easy avenue for it). We know the MPAA was trying to get state Attorneys General to go after Google. A Democratic one from Mississippi got caught using basically word for word prepared stuff given to him by the MPAA, and made a big bluster until he got caught redhanded. He was part of a pretty bipartisan group that had signed on over that issue until it fell apart after the MPAA link was revealed.