What a strange statement. "We support their right to criticize their working conditions, only actually we don't at all"
Other major tech firms have done the exact same thing when employees have raised concerns.
They make it clear that they won't retaliate against you if you don't do the wrong things, but they won't actually enumerate what those wrong things are. It's like an extended round of the Chairman's Game. [1] [2]
[1] The game forbids its players from explaining the rules, and new players are often informed that "the only rule you may be told is this one". https://en.wikipedia.org/wiki/Mao_(card_game)
[2] The game is named in honor of a famous politician who was very well known for coming up with a lot of rules for his subjects to follow, without bothering to explain to them what the rules were.