> How is it ironic? No protocol in the world can force anyone to delete anything from their own device.

You may have noticed the constant pushing to remove the user's access to their "own" device.

Forcing people to delete things from their own device is the whole concept of the Snapchat protocol, for example. Snapchat fortunately doesn't offer an OS and can't meaningfully be part of this push, but they make a convenient illustration.

You can check out Snapchat's bug bounty policy here: https://hackerone.com/snapchat . On the list of ineligible vulnerabilities is "screenshot detection avoidance". That's not a bug (because there's nothing they can do about it), even though it is their product's selling point.

Sometimes stronger companies want similar things, and they try to do something about it.