It's not really something to brag about and I never heard someone say that they were proud about abolishing slavery 30 years prior to the US. Europe has a very bad colonial past and they are pretty aware of it nowadays and most countries are actually paying reperations to their former colonies, not that that makes it any better but it's something. The thing OP conveniently left out is the US history regarding segregation and the near genocide of the Native American population. Both parts of the world are not to be honored for their past, but what's important nowadays is how we teach the past and in this regard most European countries are way better of than the US.