Other nations are sick of American/Western influence in their politics - which is vast and extensive, and: undeniably corrupt.
A Multipolar World is one in which the sovereign rights of nations are respected and not superseded/subjugated by extra-national entities/agencies which do not answer to the democracies or indeed legislature of the nation involved.
A unipolar world is one where a single nation can call up a collective cabal to form an imperial army and invade and destroy countless other nations around the world, and not a single other nation can stand against that cabal and bring its war criminals to justice.
A Multipolar world is one in which small countries do have a choice of their own - and they can thus choose to eschew American hegemony. That is happening across the globe in spite of all attempts by America's hegemonic organs to maintain the iron grip they have had for decades over the worlds poor. Thankfully.