The point is to avoid the creation of a multipolar world order. The point is to counter Russian/Chinese cooperation and the potential for future Russian/Chinese hegemony. The US seeks what it calls "preponderant" power in all regions of the planet. This is the word used. What they mean by that is the ability to carry out a "precision strike" with conventional weapons on any geographic point on the planet within 10 minutes. The US views European reliance on Russian gas and Asian reliance on the Belt and Road Initiative as a threat to US preponderant power.

How the US seeks to acquire preponderant power is by through "inter-operability" which is joint training exercises with every military on Earth, and the subordination of all local militaries to the NATO hierarchy.

As others have pointed out this is all very profitable for US military industries, as well. As well as non-military industries. Colonialism has been softened and whitewashed by treaty organizations which appear consensual but they aren't. The US is willing to replace local elected leaders with leaders who will join NATO, take loans from the IMF, work with the CIA, etc.

Why are they willing to risk nuclear war over this? Probably because they're short sighted, selfish, and on institutional autopilot. individuals within these organizations subordinate themselves to larger goals that have been in place for decades and aren't willing to risk their careers by questioning the goals. Simple rhetorical narratives like "spreading democracy" and "protecting our allies" and "providing aid" are enough extinguish any doubt.