Why are people protesting the assassination of George Floyd in countries other than the USA?

Because they empathise with Americans. The injustice of it was shared across the world. And with the past ethnic movements of people around the world has highlighted the issue.

Social injustice isn't "country specific". When the injustice reaches the level of Floyd, much of the world gets inclined empathy/sympathy. Remember the Charlie Hebdo in France? Many people changed their avatar w/ the French flag on fb in support. This is what concerned citizens do. Activism remains between elections. If you don't care, you do nothing. If you're complicit, you applaud.

Several reasons, all of which have combined.

Genuine abhorrence at the murder of a man at the hands of the police.

The need to bring to the attention of their own countries police forces/governments that such actions would not be tolerated there, or to bring to light those police forces inherent actual or perceived racism.

Overall disgust at the actions of Donald Trump and his band of lackeys over the past few years - most protests have centred on US embassies.

An excuse to get out and about after months of lockdown due to Covid19.

- cooped up inside too long avoiding corona virus

- we're outdoorsy

- being the USA 's neighbor we left bad to them so rioted too, shows we're stupider

[closest we've had to racism was someone tripped a chinese pedestrian... it even made the news with the security camera footage, omfg i laughed, the usa is rioting because a cop kneeled on a black guys throat - meanwhile in canada we're tripping elderly chinese people

https://bc.ctvnews.ca/video-released-by-rcmp-shows...

I've been asking myself the same question. And since the "protests" have arisen so quickly, the only answer that I can find is that some natiion is behind the "uprisings". - During the "cold war"  it was incidents in Europe which were immediately echoed in the US (such as the "SANE" protests) instigated by the Soviets. Since Syria and the UN were among the first to  "condemn" the US, this suggests that Russia or Iran (or both) are behind the incidents taking place right now ... And I hope that the CIA get on the matter as soon as possible.*