You said this:

> we were the colony to finally collapse the system after many centuries of it being standard across the world.

That is blatantly false. That was my point. You are right the Europeans weren't angels, but you were absolutely wrong there, America was the colony that was dragged kicking and screaming to abolish slavery long after everyone else had already done so, it absolutely wasn't the colony that finally collapsed the system of slavery it was pushed by everyone else to end it and then still had to go through a civil war doing it.

The American colonies supplied the Brits with cotton. The system was setup to do so by UK. UK was buying the slave picked cotton well after they abolished/outsourced slavery.

The UK even continued slavery in Indian colonies until 1843. They only abolished sugar plantations because it was not profitable anymore.

If the American colonies didn't rebel from the UK, they may have not abolished the cotton plantations themselves because they highly depended on it.

The US didn't "actually" abolish slavery until the 1940s. This is only partially your fault for not knowing, the US school system turns a blind eye to neoslavery in the post war era with the technicality that slavery is still legal for prisoners and that pretty much any crime could lead you to be enslaved in the south if you were the incorrect race.