And much of the world is more left-leaning than the US.
For example: Many parts of Europe and South America, China, India... all places where socialism is not a dirty word, and where they actually have viable communist/marxist parties even.
Unfortunately, being economically on the left hasn't prevented some of these places from being susceptible to the cancers of xenophobia, nationalism, and racism, adherents of which would find Trump quite appealing.
For that matter, why would a collectivist country with deep ideals of social conformity and politeness (to the point that it's baked into their language) reject "SJW" ideals? What would "SJW" even mean in Japan?
The US ain't "left-leaning" though. The left in the US is almost right elsewhere.
Then, when some people sympathetic to Trump internationally saw that MAGA hats were 1) a marker of the "Trump tribe", and 2) annoying to their perceived ideological opponents, they too took them up. Thus things like QAnon and MAGA spread memetically to some of the protests seen in the last few years in Europe.