Nostalgia isn't what it used to be, but I'm sure that 10 year old boys today have something similar to argue about. There's nothing inherently wrong with any of this, but it's a reflection of some basic human tendency towards kinship or tribal identities. Several of the authors in Moral Markets discussed so-called "evolutionary" tendencies towards reciprocity and cooperation in small groups. One stumbling block that we kept having in the discussions was the transition to market values when you aren't trading just with people who live in the same elementary school district or have the same tatoos.
Another problem with kinship and tribal reciprocity is there is no doubt that Biblically it is, standing alone, morally insufficient. Tribal cooperation and reciprocity can be the source of great evil. Warfare is an example of a massive success of in-group cooperation and the suppression of free-riding. Unfortunately, I find that I still have a knee-jerk reaction to stereotype people by the kind of cars they drive. But, reaping what I sow, what if everyone judged me by the boring, practical un-trendy Hyundai that I drive? (OK, even a stopped clock is correct twice a day). If it isn't cars, don't Americans still have a propensity to judge people by their jobs, their cell phones, their clothes, their zip-code? If morality is merely reciprocity among our kin group, it's not enough. (One of the features of the marketplace is that it tends to dampen tribal identities and cooperation that stops at the village gate. Think of that the next time someone makes the argument that we have a moral obligation to "Buy Locally." What would Jesus have said about a Judean campaign to establish justice by refusing to "import" food from the Samaritans?)
Jesus' preachings are a repeated warning against cooperation that is merely reciprocity or love that stops that the zip code boundary. And left to our own devices we are very good at defining and observing group boundaries. My friend Brad Hansen has been posting portions of his sermons on Jonah, which is a screed against tribal restrictions on God's mercy. It's right there in the middle of the prophets of the God who was, in so many ways, defined as the God of Israel. Once again, we see that Jesus came not to overturn the Law and the Prophets, but to complete them.