I think this is probably correct on the balance of probabilities but I have 2 concerns with it.

Firstly the “it would be illegal to listen” argument feels absurdly naive. Whilst almost certainly true, it only “matters” if the penalty for the crime is meaningful in context. Jail time for Zuckerberg? Probably don’t do it. A fine? Probably do it because it will likely be immaterial to the upside.

Secondly the parody-like definition of what “listening” actually means. No one is thinking a warehouse full of humans with headsets transcribing conversations and picking matching ads. An AI is perfectly capable of transcribing at scale and near real-time and linking this to keyword matching and ad-serving.