I don’t think it’s been a matter of lives dying or who lives are dying. Not for anyone who isn’t Ukrainian (after all then Palestinian, Yemenis, Ethiopian, and other states in conflict would matter as well). It’s about what it would mean if Russia is not only successful but met un challenged. The last time Europe as a continent allowed appeasement the whole world eventually got pulled into the second greatest conflict less in the span of 50 years. Another one would be devastating since a good some of the actors have world ending weapons to use against one another.