And I strongly disagree. Debian users and maintainers are by far the most helpful and pleasant people to work with and there would be way less annoying bug reports if other distros would work the same way.

"make it more obvious that users should file bugs with Debian and not bother the upstream authors" Uhm, how much more obvious should they make it? If you go to https://bugs.debian.org, click on the "how to report a bug" link then you will get to a page that concisely explains all the important points about bugs (which is a really hard to do actually!). The headline of the fourth note reads "Don't file bugs upstream".