Where do I deny the brutality of white slavery? I was criticizing the argument, not the conclusion. If you accept a conclusion is true, you ought to be especially vigilant against bad arguments that allegedly support it. A willingness to accept bad arguments just because you like the conclusion will turn your brain into mush.

For what it's worth, I do think it is very difficult to draw sharp lines between slavery and other forms of servitude. See Jonathan Brown on this.

https://www.amazon.com/Slavery-Islam-Jonathan-C-Brown/dp/1786076357

But I also feel that as bad as Irish indentured servitude was, African-American Slavery was significantly worse once the difference between the two was sharply codified.