If the US and France are going to meddle in Russia's elections and affairs, what is the big surprise if Russia does the same?
Insofar as who benefits from "isolationism" and breaking up western [military] alliances, the answer is me, an American worker and taxpayer. I gain nothing with my tax money going to kill or rape some Vietnamese farmer, or overthrow an elected government in Ukraine.
Trump has a lot of negatives, but that does not apply to whatever notions he has of not getting the US involved overseas militarily more than he already as.