I don't really understand your concern. Why is it too late if you have received one of those messages? You don't have to open it. In fact you can delete the message unopened, while the other party can clearly see that you didn't open it.

The point is if you want to report someone for it for sexual harassment, which is exactly what it is, then the disappearing message is a problem.

You don't just ignore it. You deal with it.

There's no technical reason that disappearing messages should prevent reporting them though - not only could reports prevent deletion of the reported messages, you could have it such that the other end has to agree/set their own disappearing timeline if someone messages them with disappearing messages on.

On the topic of unsolicited messages though, I prefer to tackle the problem at the source - it shouldn't be possible to message me at all if I haven't given you an invitation to do so, and invitations should be individually revocable. (This would be a big departure from the familiar phone number model, of course)

It's a bit difficult when you use the technology to run groups of unsolicited people. There is inevitably an inclusion boundary there.

Technical reasons don't trump social and human reasons. There's a compromise somewhere.

You can just screenshot it if you need evidence of its existence for some reason.

The point is to spare the other party the hassle of having to think about their opsec after-the-fact, not to trap them in a setting they don't want.

And have a reminder of it everytime you open your pictures app? Or if you're scrolling through to show something to someone else, it's hard to mistake a penis for something else even when it's a thumbnail if that other person sees.

Yeah. I prefer my phallic reminders in the messaging application where they belong, seeing them in the picture album would just be horrifying.

... You can't see if a dick pic is a dick pic unless you open it?