In my mind, the tribe aught to be constructed out of people who 1) care about you, which is accomplished through shared experience 2) who understand you - that is, they are similar enough that when you say something, they hear what you meant. There's no vast gulf of un-shared ideas and thoughts and notions that separates you, and inferential distance is short.

I definitely see the importance of having one, but in my experience race is a pretty poor proxy for what I talk about above. Shared culture is better, shared experience is best, and optimally those co-occur. (Genetic) family is a decent method, since you're likely to match in personality as well as culture, but even that is a proxy.

I suspect you are somewhat overestimating the degree to which people in other racial groups identify with each other. Two random Indians in India don't care about each other more than two random whites in America. That's because the "white" category (or the "Indian" category) is too large for tribal affiliations to build up. Granted, they'll understand each other better than they will, say, a Japanese person, but baseline friendliness levels are pretty much set at "stranger". Minority cultures tend to have a different situation, since there is a very limited number of people who belong to their group, so it becomes an easy schelling point for a community to cluster.

Essentially, your tribe should be a group of <200 people, in close proximity, who share a large number of things in common with you in terms of psychology and knowledge. To the extent that people within Western culture are "damaged" by modern life creating a situation where very few people consistently come into contact with more than 1-3 other people (the same people each time), I agree, but I don't see a racial identity as a workable solution at all. Humans really don't form tribes that large in nature, although you can get sort of a hollow illusion of identification by aligning yourself with some sort of abstract concept.

So my answer to "what are we" is basically, [insert church here] [insert small rural home-town here] [insert college here][insert secret-club here], or whatever it is that your social hub is primarily based around. Ideally you can assume people in those groups share a certain understanding with you... and if you don't have that, it's probably because modern life has forced you to trade off that stuff in exchange for mobility, and you should try to find ways to acquire it.