The mental and ethical lines are clear when I hand content to a server, that's a contract I can understand and agree to. When it runs on my device, even if it's because of the option to send it to the server, that feels fuzzier. As Ben Thompson put it it's the difference between Capability and Policy.
This is now rubbing in our faces that the privacy is only in the policy, not the capabilities of the software. And the capabilities of propriety software are pretty knowable, through a combination of inspection and long term observation.
The end result isn't any different today, but it highlights the political position that Apple and others are being put in. I honestly don't fault Apple for this on anything except their clearly poor messaging, but they are getting pulled from all sides by governments who don't like the idea of them actually implementing a fully closed and end-to-end encrypted system for user data.