I didn't ask for proof, and I think it's reasonable to demand a lot of evidence before you believe it when someone tells you they've changed. What bothers me here is that there's no articulation of that standard, just a rejection of the idea that a public statement is sufficient.

To make it more concrete: let's say that Facebook ended all of the practices the author objects to, but told no one. Clearly the author would not endorse Facebook.

Taking that a step further, the author clearly is not convinced by Facebook's public statements. So if Facebook ended all of those practices and then put out a public statement to that effect, the author would likely not endorse Facebook.

What's next after that? How do they prove trustworthiness? I don't know. I'll bet Facebook doesn't either, and that's a bad outcome because now they have no incentive to actually improve.