No one fails to make this "hey, it's a private company" point in these discussions. It's always brought up when someone is criticizing a tech behemoth for censorship of some kind, and it's nearly always a non-sequitur.
Guess what? It's totally fine and valid to criticize private entities even when their conduct is perfectly lawful.
Thought experiment: imagine eBay and Amazon started to promote Neo-Nazi literature on their home pages in the same way that they now promote anti-racist books and such. What would be the appropriate response: outrage, or "bUt iTs a pRiVaTe cOmPaNy!!!"?