They can be, but it depends on the company's culture. I personally prefer to go home and cook for myself, and when places offer free dinner, I worry that it comes with social pressure to stay and eat there, which I'd prefer not to do. If you have a family it's a bit less of a worry (you have an "excuse" for leaving to go eat with your family), but if you're single, there seems to be this expectation that of course you'd love to eat dinner at work, and you must be somehow weird if you prefer to cook for yourself at home.

Just to chime in, there is zero pressure at Yahoo to stay and eat dinner on campus. In fact, not too many people stay unless there was an event going on before hand or something. Most people just leave. But as you said, it depends on the company's culture.

What about the opposite, are you outcasted like a freak if you abuse the free services and eat all your meals there?

Nope. I'm an intern there and usually work ~10-6, call my girlfriend back home/hang out for a bit with people, eat, and go home. There's really no judging, everyone seems super chill.