If you have an OS which works perfectly until you install a piece of software that doesn't obey guidelines, then yes, I'll blame the software and not the OS. If that makes me like ssolie then that's just fine.
So if I write an OS, and provide guidelines to developers, and then someone writes software that ignores those guidelines, and it breaks a future update - is that my fault or theirs?
This is very true but it became too much when a user had issues with IBrowse IIRC that has worked since forever and still does. Then it must be something else. Also it isn't always very nice to just say "it isn't our software so not our problem". The issue could be something MUI related for example so in that case is it not an issue that should be handled by the OS developers? At least try to help.
If it is some nasty tool from 1991 then I agree though.