I'm not surprised they were fired. The environment has become so toxic.
In France, I personally pay my interns (no great credit to me though, it's a legal obligation), give them a bonus (usually one month's wages) at the end of the internship unless their performance / attitude has been abysmal, and make sure I devote some of my time to training them (although to be faire it probably averages under 1h a day). It's probably not the best deal in the world, but I certainly wouldn't call slave labour...
Unpaid internship. Aka exploitation.
"Managers are assholes" is not very valuable information, you can pick that up from sitcoms and Dilbert. But you can learn a lot from bad jobs and the mistakes of others, including managers.
The "managers are assholes" bit was meant as a joke, and I learned loads from that internship. It's just that when you're that young and self centered, you tend to see what you didn't get rather than what you did.
Of course not. But unpaid internship is always exploitation.
I've only been alive a few decades and I've seen the corporations convert "entry level jobs" into "internships" in that timespan. So it is exploitative and it is a form of slave labor.