The clearly false part of the statement was calling slaves second class citizens. They were not any class of citizens. They were PROPERTY. They were no more a citizen than a car or a donkey or a house would be.

The part you have quoted here, I initially called highly dubious and requested examples which you claim you cannot give because "there were no specific laws for prosecuting the slave owners". If there were no specific laws under which slave owners could be prosecuted for abusing slaves, then how could they be tried before the juries you claim refused to convict them? That makes no sense, and by that analysis, this part of the statement is also almost certainly false.

I think you are confusing the Fugitive Slave Laws with the Jim Crow era, which followed the Civil War. There actually are examples of all-white juries during the Jim Crow era who failed to convict white defendants on trial for lynching black citizens. And yes, they were citizens in the JIm Crow era, but not during slavery.

Rather than insulting someone who has researched and written on both of the topics when you are clearly in the wrong, I strongly suggest getting your facts straight and correcting your article.