I doubt 4-6 hours extra per day (13-14 hour days) is typical.

Aside from that quibble, look at it from both sides:

The company spends a few hundred dollars a week on meals and gets 5-10x return on that money. Everybody agrees this is a good deal for the company.

The employee trades a few hours of his life for food. The hours he works, he would not have received any money for anyway unless he was working another paying job. The employee is trading "opportunity costs" (imaginary value) and receiving substantial value in "free" food.

If the "opportunity cost" of those extra work hours are sitting in front of Netflix watching zombie movies, he probably got a good deal trading that time for food. If the "opportunity cost" is starting the next hot startup, he got a bad deal.

Talk to anybody who works for a company who offers meals. 12-14 hour days are typical at most. Not officially, of course, but that's the point. Raw ROI aside, the real benefit of offering meals is to foster the type of culture where the company is "home." You eat there. You exercise there. You socialize there. There's no need to have a life outside of work, so a lot of the employees don't have one. If you're always around your work and people you work with, chances are you'll spend most of your time thinking about and doing work. It's a way of getting 14 hour days out of people without them realizing it or complaining about it. In that way, it's absolutely a form of "mind control" (operand conditioning).

Most would say the above is harmless and it benefits the company, which benefits the employee, so why is it such a bad thing? It's bad because this type of culture makes it extra easy for engineers to burn out.