You have been using “moral choice” as a proxy for “appropriate for comment by the Church.”
It really works best if you just assume I really mean exactly what I write, and not reinterpret my words to mean something other than what I have said. I use “moral choice” to mean exactly that: one is making a choice that is either moral or immoral, just or sinful. This is not complicated.
But that is clearly not so because as you note right here, the decision to appoint seven men was not strictly a moral choice. But you have yet to declare that the decision was not appropriate for the apostles for that reason.
No, the decision to appoint seven men was clearly not a moral choice; it was entirely a practical one, but the mere fact that it was solely practical cannot mean it was therefore inappropriate for the apostles to make such a decision. They were responsible for addressing all of the practical difficulties that arose with serving the church. It is not the fact that a choice is practical that makes it inappropriate for the clergy to address it, it is a question of whether the issue falls within their sphere of responsibility. Matters of the church, yes; matters of government, no.
I am not contesting the point that one may disagree with the bishops on their gun control message. I am only disagreeing with the claim that it is inappropriate for them to comment about it at all.
You have been arguing for hundreds of posts that this is a moral issue. If that was true then when guidance is given by the bishops it comes with the presumption that they are laying out moral choices: allow this, don’t allow that… But as you yourself note, we are free to disagree with the bishops suggestions, a position which refutes the notion that the bishops are in fact giving moral guidance.
Bishops speaking out on non-moral concerns do a number of things, all of them unhelpful. They imply that their opinions represent moral positions - which by implication means that contrary positions are immoral. This changes the nature of the discussion away from what is better to who is better, with anyone holding the “immoral” position clearly in the latter category. It poisons the discussion from the start and severely reduces the possibility that the talks can be productive. It provokes charges like “cafeteria Catholic” and “denying the church”, and other equally silly and offensive slurs. They reduce their own credibility by blurring the line between their political pronouncements and their moral ones.
Really, their persistent involvement in political issues has nothing whatever to recommend it.