Multi-polarity is generally code for regional hegemony. That's great if you're the regional hegemon. Not so much if you're the hegemon's neighbor.
America is a maritime power. These (think: Carthage, Venice, Portugal, the Dutch and Britain; counterfactual: Japan) have historically relied on trade, and trading outposts, to project power. As such, they're a natural friend of small countries resisting regional hegemony.
>natural friend of small countries resisting regional hegemony
Consider Cuba or Venezuela and their relationship to the USA.
Objectively, yes. In no small part because maritime powers tend to knit together alliances, not annex and colonise the way land powers do.
> Consider Cuba or Venezuela and their relationship to the USA
In both these cases, we are the regional hegemon.
There is no organization that can prevent one state from going to war with another, I believe a multi-polar world would inevitably lead to a global scale conflict.
Was the humanity better off during the Bi-polar era of the Cold War, with continuously escalating nuclear threats and proxy wars vs 1991-2010? What about the multi-polar world of 1919-1938?