this is true in some sense, but then, America isn't the only place that exists. If you go to the near-middle east region, there are places where blacks have enslaved whites, or even their own ppl. And some of these people were the same Africans who stole kids from their homes for the purpose of selling them to whites going to America (which is how the American slave trade even began in the first place). Also, the word "slave" actually comes from the Slavs, who were Caucasian.
The notion that black people have always had it harder than anyone else is just simply untrue. There were the Jews in Nazi Germany. There were the citizens of the Bolshevik Revolution who either died or had to live through a USSR reign of Lenin and if they survived long enough, Stalin, who was even worse and just killed people in droves just to instill fear. Stalin alone killed more ppl than even Hitler did (including Holocaust numbers), and thats not counting all the forced abortions he caused, resulting in the deaths of millions of babies whose moms didn't want to give them up.
And Mao's takeover of China was very much like Hitler's takeover of Germany; he picked a demographic of ppl to rile the public against and began persecuting them in droves after taking power, just four years after China had finally been freed from Japan's oppressive takeover (which was another event that sucked to live through). Mao alone killed more ppl than Stalin and Hitler combined, and then some.
And then there's the Kim dynasty in North Korea, the most oppressive reign on Earth. The population of the region of North Korea decreased by 2/3 when Kim Il-Sung took over bc many were either killed or they bolted to South Korea.
There are ppl that after hearing all this, are still convinced all blacks have had it the worst simply bc black. Some ppl have even suggested that blacks have it the worst now. If someone really thinks that, I dare them to go to North Korea and bring a Bible or the Quran with them. It won't end well. See, in America, we are all entitled to free speech, something we take for granted. In China and North Korea, that same freedom is non-existent. You will be persecuted for not agreeing with the government. And believe me, if you think slave torture was bad (and it really was), you really don't want to know what kind of torture happens when a government gets like the USSR's or Nazi Germany's or WW2 Japan's or China's or North Korea's where no one can question what the government does.