It's not particularly insightful or correct. It is absolutely true that our traditional NATO allies (except maybe Turkey) cheapen out on defense spending in reliance on U.S. protection. Their leaders admit that themselves:
https://apnews.com/0229dd7556264040810d9e7f96f3aa0a/France%2...> In a speech to French ambassadors in Paris, Macron said “Europe cannot rely on the United States only for its security. It’s up to us to meet our responsibilities and guarantee our security, and therefore European sovereignty.”
Nobody has decided that "human life can ... be more peaceful" without military superiority. Now that Trump has given Europeans reason to be skeptical about America's commitment, there is already a push to build up Europe's military forces. Macron will increase defense spending by 35% over six years, reversing a decade of decline: https://www.reuters.com/article/us-france-defence/france-com...
https://www.euronews.com/2019/04/29/eu-countries-increase-mi...
Ukraine is not a particularly good counter-example of that theory. First, Trump is the first U.S. President to exhibit some isolationist tendencies since Carter. But European disinvestment in defense has been going on since the USSR collapsed. Second, Ukraine is a former USSR country with a complicated history with Russia. It's not indicative of whether the U.S. would come to the defense of a real U.S. ally.