Ozzie,
Good question. After departing in 1987, I attended various services of multiple religions for lots of different reasons. Most had a "social hour" afterwards at which home-baked goodies (yippee-nearly always there is chocolate cake or brownies) and weak de-caf (for the old-timers) were served. Most facilities had a room or hall called the "the social hall" just for this purpose.
I figured that the true reason why this does not occur at Kingdom Halls with the JWs goes a lot deeper than the reasons you suggest. The deeper reason is that this sort of socializing might make people come to meetings for the wrong reasons. These after-parties would take away from the true importance of the meetings, which is to be indoctrinated to do more to bring in more converts, who in turn bring in more converts....
There has been, and always will be, a taboo on all the things that naturally bring joy to humans. Enjoying a nosh and a schmooze together is one of those things. There has been almost as much print space alotted to controlling "get-togethers" as there has been to discouraging secular goals. People might come to meetings for the wrong reason, to get a brownie or chocolate cake (let's face it, no one comes for the weak de-caf).
This question hits to the essence of why the WTBTS does nothing to help non-JWs in need. They love their little phrase about not casting pearls before swine. They think non-JWs, or the "spiritually weak" JWs might just come for the goodies, thus elevating the nosh and schmooze higher than the meeting itself. If you don't offer anything but the religion, then you know their true motives for attending (to be brain-washed). If you don't offer, food, clothing, shelter to the needy, then you know they are coming to meetings for the "right reasons."
What I think is missing from the JW religion is that value of social connection and pure charity-giving while knowing you will get absolutely nothing in return. It is not what the religion can do for you, but what you can do for the religion. Don't you think it is odd that most religions build their facilities with social rooms, kitchens, classrooms, outdoor gardens, etc. It fosters the notion that the "church" is a place for community, not just "religion." However, JW facilities are just parking lots, meeting rooms, lavatories and book stores. In fact, if people are not in their seats in the Kingdom Halls, there is usually very little room for them to mill around visiting in the aisles or in the back. (Ever notice that? The Halls are designed to discourage people from arriving early and lingering after...)
So there you go. What I think.
Shoshana