The original comment regarding “bonding” was equally anecdotal - you just agree with it, and therefore perceive it to be an argument.
Rationally, there’s no inherent reason that free lunches promote “bonding”, and no inherent reason that teams that go out to lunch won’t bond. It’s just cargo culting and post hoc rationalization for people liking free food.
I absolutely brushed shoulders with more coworkers when I worked at a company that had a cafeteria (this wasn't even free to us). My current teammates eat together sometimes, but unless it's an 'event' it's just 2-3 people, and always someone who wont go due to diet or financial reasons.
The upstream comment even said free lunch "promoted" camaraderie, not "is the only way it can happen."