GP is saying that calling the prisoners "workers" is incorrect, and that it is more accurate to refer to them as "slaves". Honestly, I'd tend to agree. There's even a little exception in the 13th Amendment specifically for this:

"Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction"

They're slaves.

The GP's point is that calling slaves forced to work in a prison "workers" is a disgusting euphemism.

No, the disgusting euphemism is still live on the original site and was allowed to stay up on HN. The submission correcting the disgusting euphemism was flagged off the front page before this submission that we're on with was submitted.

Your correction to the GP comment is incorrect. This is an article about slave labor and submitting it under titles that suggest otherwise is misleading.