Funny you mention crossbows; the Church at one point in time tried to ban them because they democratized violence to a truly trivial degree. They were the nuclear bombs and assault rifles of medieval times.
Also, I will take this moment to also mention that the "problem" with weapons always seem to be how quickly they can kill rather than the killing itself. Kind of takes away from the discussion once that is realized.
It's almost military precision.
On behalf of dead WWI soldiers I find this offensive.
Brutal murder is low tech.
They are much less likely to.
We have instinctive repulsion to violence, especially extending it (e.g. if the rock does not kill at the first blow).
It is much easier to kill with a gun (and even then people need training to be willing to do it), and easier still to fire a missile at people you cannot even see.
It’s like the original massive scale organization.
(Thankfully in the US we worship the 2A and its most twisted interpretation. So our toddlers do shooter drills. /s)
Or, gather a group of people, tell them to find a rock, and go bash the other sides head.
It's that we have technologically engineered things that are destructive enough to get even past that threshold. Modern warfare in particular is insanely energetic in the most literal, physical way - when you measure the energy output of weapons in joules. Partly because we're just that good at making things explode, and partly because improvements in metallurgy and electronics made it possible over time to locate targets with extreme precision in real time and then concentrate a lot of firepower directly on them. This, in particular, is why the most intense battlefields in Ukraine often look worse than WW1 and WW2 battles of similar intensity (e.g. Mariupol had more buildings destroyed than Stalingrad).
But even our small arms deliver much more energy to the target than their historical equivalents. Bows and arrows pack ~150 J at close range, rapidly diminishing with distance. Crossbows can increase this to ~400 J. For comparison, an AK-47 firing standard issue military ammo is ~2000 J.