I was mostly meaning the first example you provided. These platforms are so good (at least they claim to be) at matching users and ads because of their extensive data collection/sharing practices. Is it cool to say "We respect our users privacy" if they are benefiting directly from another companies less privacy respecting practices?

They have no choice. There is no technical way for Apple to monitor what data apps are sending out without doing something like MITM every connection which is a million times worse.

So they have to rely on a punishment model where they demand apps provide a privacy policy then kick them off the store if they fail to comply with it.

I think he was asking whether Apple itself buys ads on platforms like Facebook. e.g., ads for Apple prodcuts.

The implication being that by doing so, they would be benefiting from the aggressive data collection performed by those platforms.