1. Infiltration. An agent or asset could be in a position of power to enact desired policies and changes, provide a backdoor or whatever;
2. Jurisdiction. The platform falls under US jurisdiction so is subject to various forms of law enforcement, secret or otherwise. National Security Letters, FISA warrants, pen registers, that sort of thing; and
3. Propaganda. US companies reflect the cultural and political values of their founders, board and management as will as the will of stockholders. For some issues there is a political divide but for many issues there isn't, most notably when it comes to US foreign policy where Democrats and Republicans are basically indistinguishable.
The prevailing foreign policy view is that the US is good and a benign hegemony and a civilizing and democratizing force. The current foreign policy bent also favours interventionism and has since World War Two.
You see this at the huge backlash you get, even here among relatively educated and informed commenters, when you dare to suggest that the US bears some responsibility for Ukraine's predicament even though Russia is of course wholly responsible for an unjustifiable invasion.
It's a real lesson in the power of US propaganda and how ingrained the benign hegemony meme (and it is a meme) is.
My theory is the first 2 points I listed above don't matter. They're of almost no importance. What really matters is the ability of the US media (and I include social media companies in this umbrella) to project US propaganda and to normalize the US-centric view of the world.