You can’t unsend an email because you can’t force someone else to delete something. Emails end up as files on someone else’s server. Claiming this is a UX issue is intentionally missing the point. If this is legitimately a foreign concept to you, an afternoon setting up postfix and playing around with it might be worth your time. Email is a protocol, not a program. A “delete” request would be just that, a request.

You can “unsend” on those platforms because the GUI does not display files saved locally, it always fetches them from the server. If you could “unsend” on a version control platform, then it would cease to be distributed version control. The code would have to live inside the VCS app (the same way messages are in memory in slack), or you’d have to give a network daemon delete privileges on your file system.

Imagine if youtube-dl used the model you’re proposing. Letting the git equivalent of “unsend” propagate through the system takes you from a redundant system to, not a system with a single point of failure, but even worse, a system with many points of failure.

Git is for helping develop open source projects, where sometimes a random gal who will never show up again fixes a small thing and sends the maintainer the diff through email. If you want a tool for the high trust environment of your individual team, git will never be what you want. It literally wouldn’t work for its intended workflow if it did what you want.