There are no rights or wrongs, this is subjective.
Locking someone up because they committed a sin(and that's what we are talking about, by the way, all these laws are enforcements of christian sins), is ridiculous, because the bible never makes any fucking sense, it contradicts itself hundreds of times and is therefor a dubious source at best.
We, as men, have hormones that tell us to kill, this is not "bad" or "wrong", this is what we have evolved to be, this is the way we have survived. Unless you want to lie to yourself and claim that men do all have this urge, that it is only "sick fucks", in which case continue no further, because I can't teach you anything, because you chose to actually ignore your own body and instead listened to your mother or some shit.
People need to calm the fuck down and stop pretending like the sky is falling when someone dies, especially some random people in eastern Europe you've never even heard of before, it ain't my problem, and it ain't your problem.
I'm personally confident that I haven't made any enemies that would care enough to hatch a scheme, and that I can defend myself unarmed against an armed opponent. But maybe you aren't, and that's why you feel all murderers should be locked up or killed, because you're scared, scared that you couldn't protect yourself or someone you love.
I pity you, if that is the case.