I hope so, too.

Among countries with populations over 100M, only the USA and Brazil were not involved in a major democide last century.

They are democratic republics, sure, and large enough to be functionally independent, but so were Germany, Indonesia and Pakistan up to the start of their respective rampages. (Arguably Russia was too, very briefly under Kerensky before the October Revolution kicked off.) So its not that.

USA and Brazil are notable among their peers for widespread citizen ownership of rifles, as well as traditions of decentralised governance. Our sample size here is too small to prove anything, of course, but I think the evidence is rather suggestive.