"Ukranians were murdering Russian people in Donbass"

Russia settled Russians in Ukraine to control/destroy it for decades (like in the Baltics, Georgia and in many different places, the usual Russian tactic). Then Russia instigated a civil war in Ukraine and finally invaded Ukraine in 2014, so there were fights in Donbass back then with deaths (Russia also shot down a Malaysian plane in 2014 from Donbass).

"Your weapons are murdering Russian civilians right now, but you don't care, why?"

Because those Russian civilians voted and supported a dictator who wanted and wants to invade Europe and re-enslave the population. And Russians loved it, they loved it plundering and murdering and torturing people in Europe before and they will again.

Russia encouraged Serbs to start WW1 because Russians wanted to invade Europe through their puppets on the Balkans, later invaded Europe in 1939 in a joint military operation with the Nazis/Germans and will do so again whenever Russians see the chance to do so.

I would prefer no war but a big wall, mile deep minefields and drone/ballistic/SDI defenses instead to keep Russians out and stop them from invading Europe again, but I guess Russia needs to first lose this war to make this a reality.