I think you agree with the OP. In this way, the tool has no ethical problem (there are plenty around how they were trained and such, but that's besides the point), the problems are with how it's used. The ethical problem is how people are behaving and how they are abusing each other, not the tool they are using to exert that abuse.

I suppose it's a little bit of a "guns don't kill people" argument.

The tools have different ranges of uses. A knife can be used to cut things. But while humans are among the things you can cut with it, there is a staggering array of other options which are genuinely useful in everyday life.

A gun can be used to, uh, make small but deep perforations at a distance, by throwing apx. 7 grams of copper-encased lead at high velocity at the target, with somewhat poor precision. Oh, and such an impact does stress/shatter the material around the made perforation quite a lot. So... this thing really can't be used for much anything except for killing animals without getting into contact with them, due to the peculiar way the life is sustained in the animal organisms. This, too, can be useful in everyday life although I personally would advise you, if you find yourself in such a situation, to try and move to somewhere nicer.