I found it clever and I welcome it. The history surrounding slavery isn't a taboo subject, what a ridiculous idea. The commenter in no way is condoning slavery.
Yep, as a black person in the USA… this sort of reads as:
“Remember those times your ancestors were enslaved?
Which relates to a history of segregation and oppression so recent that your parents were alive when it was overturned? You must remember it since it’s still championed by secessionists and is the cause of ever present police brutality.
Remember that? Well wow, do I have a funny joke for you!”
Long story short, there are other jokes that could be made.
They're just saying they don't want to have to think about slavery when choosing software which seems not unreasonable to me.