I've been an intern many a time, and most of that was unpaid or very marginally paid. The intern blues is real. You're expendable, you're lowest on the totem pole, and you don't command respect. The lack of pay is just the cherry on top. Yes, you get to learn new skills, build your resume, and maybe meet some people who will help your professional life down the road. But it's a huge price to pay. Thankfully, unpaid internships seem to be falling out of favor as folks have realized that they're not workable for most people.
But as long as there are employers, there will be people who take advantage of free labor. And they will squeeze it for all it's worth. But the key difference between an internship and a real job is that you can't have the same expectations of working overtime and going above and beyond. It just doesn't work that way. But that's exactly what happened in this recent Reddit story.