Nah, the simple and sole reason people dont speak about tribes on specific people is because these are people are supposed to live in "civilized" states. You will never hear someone calling the modern Bavarians a tibe, nor the Basques nor the Han Chines. But you will hear them calling the Tuaregs a tribe, or the Dinka, or the Amazon Indians. Simply because they think these people are primitive. Thats why they get called "tribes".
Many people who are supposed to be "tribal" (primitive) still lived in cities.
You are, of course, wrong. People do speak about the Bavarian as a tribe, part of the germanic tribes. Slavic tribes settled the balkans.
The problem with the term tribe is the connotation that came with it in the 19th century, which implies a unilinear cultural evolution of societies. That theory is bogus, of course, but it's use to denote a society with "simple" organized society or a subdivision of a group is completely valid. That theory has long been dissociated from the word. And in fact the word is still in use by many scholars.
If you want modern examples of non african/non-native americans, there's all over the world. Chechens, for example, are an ethnic group. They identify as such. But some of them still have tribes - they carry symbolism for that. Arabs often also use it (tribe) and even the flag of the Republic of Adygea has 12 stars representing, you know what? That's right, tribes. You can have an ethnic group (like the Oromo or Chechens) who have further subdivisions, that they recognize themselves, that is what we (and them) call tribes. Which is the original use of the word, and it's very much in use.
"The term originated in ancient Rome, where the word tribus denoted a division within the state." Using the victorian meaning is something you are doing right now, don't imply it's what other people are doing.
The reason we call basques an ethnic group and not a tribe isn't because of the racism you yourself give to the word, but due to changing dynamics in these groups.
"Ethnic group is a particularly appropriate term within the discussion of modernizing countries, where one's identity and claims to landownership may depend less on extended kinship ties than on one's natal village or region of origin."
That's why Basques are not referred to as tribes anymore. Though they were referred to as such, and you can see such references in the literature.
"Basque tribes such as the Tarbelli in Dax and Baiona, the Sibusates or(...)"
Basque Diaspora: Migration and Transnational Identity. From 2005 by Gloria Pilar Totoricaguena.
No, the author isn't a racist like you like to think for using
tribe. The term is used because it's a valid term which implies (for societies in general) societies with simple organizational structures and for an ethnie (like the Chechens) a subdivision which today still has meaning for the reasons explained above. These subdivisions in some ethnic groups vanished with time, kinship and local ties vanished, so only the macro determination remains. You can't have subdivisions for them anymore.
In fact, the term is still taught around the world, you can see examples here
http://anthro.palomar.edu/political/pol_2.htm
and see there's no implied racism.
The implied racism in the word is something
you give to it, not the ones that used the word. Of course there is a school of thought of more politically correct researchers who also agree with you, I'm aware of that, but like you, they are biased towards it because they can't disassociate the word from the 19th century use like most people did. Biased sources (like citing a non scholarly article in a site called "tolerance.org") don't support your claim that tribes don't exist. They did, they still do, no matter if you believe in them or not.