what's a "white society"?

The sorts of orderly, high-trust societies that White people create (in Europe, or elsewhere - e.g. USA, Australia, and Rhodesia are still fundamentally "European" in character), along with their basic institutions: patriarchy, monogamy, Christianity, and so on.

Whites have been killing each others over petty squabbles for centuries just like any other races.

War is a fact of life. Whites do tend to be better about impulsive violence, though. Over the course of centuries, Whites (and Asians) executed their violent criminals, and this had a lasting effect on the gene pool. Whites (and Asians) have a greater tendency to be obedient and "civilized," and this is a big reason why these societies are nice places to live in, although it's somewhat harmful today - Whites are following their trusted authorities and institutions, which have become corrupted, to their doom.

I don't think so. Hitler was a mad man and a complete incompetent, a bit like Trump.

Trump is not a dumb guy, but he's also no Hitler. Trump was a client of Jeffrey Epstein, thus he was subject to the whims of Jewry. They noticed a rising current of nationalism, and Trump arrived to be a sponge, to absorb and neutralize White identitarianism.

And a coward, since he committed suicide... at least his generals had the decency to let themselves be executed.

Goebbels, Goering, and Himmler also allegedly killed themselves. I won't fault anyone for choosing to avoid torture at the hands of Bolshevik Jews. And there are many traditions of honourable suicide - seppuku, Socrates, Masada. Although, I do entertain the idea that he retired to Brazil.