IANADev, but surely if they were going as deep as understanding patches they'd practically be a project maintainer rather than a package maintainer. Expecting package maintainers to have even reviewed diffs seems like high expectations. I wouldn't expect them to do more than the actual packaging.

Weak words seem appropriate.

I've hacked together a couple of packages for personal use but didn't even go so far at to look what language the code was in. I'm assuming a lot of packages from ppa-s are produced in an automated way with no code review, and depending on your distro that might also be true of some principal libraries.