Generally white males. However they are basically the only group in history to actively go against what was in their best interest for the betterment of all.
I have been reading Gulliver’s travels recently. It is very interesting in that it was written in around 1720, a time period where slavery was still common. The main character is enslaved, freed, enslaved again, almost worked to death, etc. and it is all taken as part of life. The way it is just accepted is fascinating.
We don’t have the same view point in the modern era, but its only because in the 1800’s and 1900’s white men decided to end those practices. Not only did they decide to end those practices in their own countries, they actively worked to end them elsewhere too. Look at the West Africa Squadron for example, it prevented 150,000 Africans from being enslaved, cost a ton of money to do so, and was a political nightmare for the British.
Basically every society to ever exist up until recently had slavery. Basically every society to ever exist had discrimination, sexism, etc. its only very recently (last 200 years) have we moved towards a society which doesn’t have that. And its basically directly white males who are responsible for allowing/causing that.