I stumbled on this interesting Canon from the wikipedia article on the Second Council of the Lantern, while I was researching something else. Unfortunately, when I tried to look into this further, most sources I can find seem more interested in quibbling over the exact weapon and language of the canon, and not that very interested in the background.

In relations to my question, obviously, if the Church passed this Canon, they believed (in some form) that it would either bring a benefit to the Christian world (like a proto-Geneva Convention, maybe?) or there was political/economic benefit that would benefit the repair of the schism between Pope Innocent II and antipope Anacletus II.

From what I (very superficially) know, neither theory quite holds up. There are some arguments about crossbows being inhumane in that time period, etc etc. However, the language seems very vague and not targeted against a specific weapon, so it does not seem to hold up. Alternatively, I tried looking into the background of both the main parties. However, both popes had a mix of nations/nobles, and I do not immediately see an obvious political slant to this, where one nation might have been able to condemn an opponent.

This leads me to believe that I am crucially missing some background information on the general belief in the medieval world. Was this some cultural belief against ranged weapons that I wasn't aware of? Or are there some interpretations of the Bible that are against ranged weapons?

As an aside, and for bonus: With the (very safe, I think) assumption that no general in their right mind is going to give up ranged weapons in their army, why did the Church even think of passing this Canon? Did they not expect that it would be promptly ignored, and their authority would be diminished in the aftermath? Or did they expect it to be ignored, and there was a deeper game being played here?