I see what you mean. My logic only really applies to the simpler programs which exclusively use the standard file descriptors. It gets fuzzier when the output of a program is an actual file somewhere.

The output of a package manager is the packages. The text it writes to the terminal is not part of the output, it's just the program's log. I haven't thought about what's appropriate in this situation. By unix standards package managers shouldn't even be printing anything to begin with.