Apple is actually not in the business of selling the data of their users. They will also risk aggravating large players in favor of improved privacy. A recent example: App Tracking Transparency [1] which makes tracking an opt-in feature to be requested from the user. To no one's surprise users are happily declining when made this offer. Companies like Facebook aren't too happy about it. [2]
Privacy and security are related, but distinct. Apple has been pushing privacy, but we're talking about security here. Typically the tradeoffs around increasing security have to do with user experience, something Apple typically does not like to compromise on.
Well, keeping things private certainly rests on the security of devices and protocols. That being said, Apple investing heavily in making security unobtrusive isn't in itself a sign of weak security. A lot of it is just well engineered and thus unseen. But documented in parts for everyone to see: https://manuals.info.apple.com/MANUALS/1000/MA1902/en_US/app...
If I somehow made it seem as I thought Apple sell data then that wasn't my intent (but neither does Facebook or Google sell their data).
However I do believe that Apple is only doing what you describe as a PR move. At the same time Apple fight other's advertising and tracking they are strengthening their own version of this. That users get something good out of it is strictly a side-effect. Promoting Apple because of this is in my opinion worse than promoting Facebook for their behaviour as they don't try to sell it as "protecting their users" as far as I know. Using an Apple phone is likely better than one Facebook had its hands on but the thinking and ethics behind is worse in an Apple product as they are successfully being extremely disingenuous towards their users about protecting their privacy.