I know it's hard to shed the received narrative that FB = evil, and even if it was easy you probably wouldn't want to because it feels good and right to reinforce that belief.

However, I think I was pretty clear.

"It was solely to see if we could make people feel less self conscious by decreasing social comparison." - the main goal

"Our hope was to decrease the pressure normal people feel about sharing their lives with their friends and family." - if we achieve the main goal, this ~might~ happen.

"We thought this might improve some long-term metrics" - on the off chance this happens, we ~might~ benefit in the long run.

Is this really different from "I suspect that the recent trend of social media platforms hiding engagement metrics has less to do with fighting 'envy' than simply allowing for more authentic looking proliferation of promoted content" ?

I think so. Seems like a pretty indirect way of driving user engagement.