Because the wanted to cleanse the Earth of everyone who wasn’t arian and of clean blood, they wanted to create a master race and systematically wipe out everyone who doesn’t fit into that concept.
Stalin was a paranoid madman, who arguably killed more people than Hitler, but it wasn’t his intention to cleanse the Earth of everyone non russian.
If you compare these two, the where certainly of the more “evil” intentions. And pretty much all Germans knew what was going on, people knew about the concentration camps and that the jews were hunted and killed. And yet the absolute majority still did nothing to stop it.
I am not sure what you are talking about, but there hasn’t been any outside reason for Germany to start the war. Probably you are talking about the story of Gleiwitz in August 1939, where polish rebels staged an attack on a radio station (and multiple other locations) near the german border.
That was a false-flag operation by german SS-agents, to give Hitler an excuse to invade Poland and start his plan for a full scale european war.
So please, stop saying there were legitimate reasons for Nazi Germany to start the war and kill all those people. There wasn’t.
And the recent massacres / genocides aren’t worse, by far not. Only people who never visited a concentration camp can say things like that…
Yes, the people these days are very ignorant of the suffering of others, but mainly because they feel powerless. We can’t always stop the massacres in the middle east because Russia (and sometimes China) is vetoing any uniliteral actions.