From what I can see here[0], her plan is to undo the mergers (so, Facebook, Instagram, WhatsApp would become their own companies once again).

And I believe you're referring to this audio[1], which I did not know about until now. Relevant quote:

> "You have someone like Elizabeth Warren who thinks that the right answer is to break up the companies ... if she gets elected president, then I would bet that we will have a legal challenge, and I would bet that we will win the legal challenge. And does that still suck for us? Yeah. I mean, I don’t want to have a major lawsuit against our own government. ... But look, at the end of the day, if someone’s going to try to threaten something that existential, you go to the mat and you fight."

[0] https://twitter.com/ewarren/status/1179118101755039744

[1] https://www.theverge.com/2019/10/1/20756701/mark-zuckerberg-...

Mobsters will fight over existential threats too, and it doesn't make what they're doing appropriate or worth defending. I'm not sure I'd go so far as defending to the death Facebook's right to be a giant conglomerate eating up other companies. Isn't that exactly the point?

I don't see an argument saying 'companies must be ever bigger, infinitely, as a moral right'. The companies might think so, very passionately even, but I would suggest they're wrong and it's a bad thing to indulge.