I do go with my people to the supermarket and then eat later at my desk...which is in an proper office room. With doors and stuff.

I mean, sure there are people who did not grew up with proper hygiene education and such but, please, this is not everyone. I want my keyboard clean because I work on it. I know when to wash my hands. I'm not 5.

And yes, it's a social thing too. I worked for several companies in Germany in almost all of them the dining room at 12 was a horrible gossip melting point. To me it's social pressure. I'm not even hungry at 12. I also don't want to have my break being filled with the latest office gossip. It's terrible...

So as you see. Sometimes it's just a different perspective and probably it's not the same everywhere.