First, he was simply pointing out that stuff (like benefits) costs money and that you should be looking at someone's TOTAL compensation (not just cash wages) and benefits.

Second, you need to look up the word "slave". The "slave wages" talking point may be what you use to describe a wage that YOU are unwilling to accept. But it doesn't make these people slaves in any reasonable definition of that word. Using that word is, frankly, an insult to people who actually do endure slavery in this world. It cheapens it. Just say "a wage I wouldn't work for and that I personally think is too low."

Finally, the people in those photos appear to be quite happy. Maybe they're getting something from this job that is better than the other alternatives they have.