"Development on Ubuntu" in the on-topic guidance refers to developing Ubuntu itself i.e. writing software for Ubuntu. This is always on topic regardless of the tools being used. I don't think that should be changed, even though the relevant expertise may be scant here.
General purpose programming questions are already off topic,General programming questions are already off topic with the exception of shell scripting which our community has extensive knowledge about, as you mentioned in your answer.
It's also on topic to ask about setting up a development environment on Ubuntu, and so on. See the pirate test.
Perhaps the wording of the page could make these things clearer.
BTW, a mod needs a lot of courage to migrate to SO.