Great Zimbabwe and the Lemba Claims

Has anyone noticed a determined effort to re-write the history of Great Zimbabwe? There seems to be a systematic amplification of the claim of the Lemba people on the building of Great Zimbabwe. The discovery of Mapungubwe in South Africa triggered this determined effort.
The Great Zimbabwe Lemba claim says: (1) That the Lemba arrived at first Mapungubwe during the period 1025 - 1225 and later at Great Zimbabwe around 1100 before the Shona people and built these cities; (2) That the Shona arrived later and conquered the Lemba and drove them out of Great Zimbabwe and possibly Mapungubwe; (3) That the Shona then started living in these cities and placing all the ancient Shona artefacts that were found at the site of these ancient cities.
Furthermore, the Lemba also have a second claim relating to their origin as a people. They are claiming that they are not African nor Bantu but Jewish people who happened to find themselves marooned by a sea of Bantu people in Southern Africa, see http://en.wikipedia.org/wiki/Lemba_people . The Lemba language is quite close to Shona language, especially "ChiKaranga chekuMasvingo", and so the Lemba actually speak a Bantu language and not a Jewish language. However, their clan names are said to be of Jewish origin. See http://www.kulanu.org/newsletters/1999-summer.pdf When combined together, the above two claims by the Lemba can be used to perpetuate the colonial and white supremacists claim that Bantu people did not build Great Zimbabwe or that if they did, then they could not do it alone.
It is important to note that the Lemba are only about 70 000 while the Shona are more than 15 million (in Zimbabwe and Mozambique and other countries). The Shona people are the most populous Bantu group in the whole World with Zulus coming second. The Shona language is the most widely spoken Bantu language on earth when we do not consider Swahili, whose large population of speakers speak it only as a second language and not as a mother tongue. Consequently, the Lemba people who once built prosperous ancient cities from Mapungubwe to Khami to Dlodlo to Great Zimbabwe are now found to be almost extinct in the land of their prosperity for centuries past.
It would seem to be more sensible if the Lemba claim were that they are a Shona group and that they participated in building Great Zimbabwe. They would also present the Jewish claim by saying that the Shona people (them included) have Jewish origins. Thus, many aspects of Shona culture and customs are quite close to Jewish ones not because of Lemba influence but possibly because the Jews were originally Shona or Lemba!
Historically, the decline of Great Zimbabwe and even Mapungubwe is attributed to over-population and exhaustion of economic resources. Therefore, one would expect that the Lemba population would dwarf that of the Shona and not the other way round. History has not yet recorded a mass extermination of the Lembas by the any other groups such as the Zulus or Shonas. That the Lemba built these ancient cities and yet appear to be almost extinct within the regional vicinity of these cities is quite baffling to me.
One of the languages that is associated with the Lemba is Kalanga. From Wikipedia, we read: "The conclusion that Kalanga is a Shona dialect is one of the most eroneous conclusions that have ever been
made in history. It will be understood that this is a battle that has been going on for over eighty years now. Way back in 1927 the Rhodesia Missionary Society wanted to create a standard Shona orthography, but
they could not agree on Kalanga being listed as a Shona dialect. They enlisted the help of Professor Clement M. Doke, then a Bantu Studies professor at the University of the Witwatersrand. After a year long study in Zimbabwe, he actually concluded that Kalanga is cannot be listed as a Shona dialect because it is too phonologically diverse from what can be called Shona. In fact, a simple test that this is true is this: those who speak the so-called Shona cannot understand the Kalanga when they speak, though the Kalanga can understand the Shona." See http://en.wikipedia.org/wiki/Kalanga_language The above could be considered to be a lame conclusion. The fact that a Kalanga speaker can understand spoken Shona while the reverse is not true may not necessarily be a good test simply because Shona is the mostly widely spoken Bantu language on earth. The Kalangas in Zimbabwe and South Africa are bound to understand Shona language since it is the majority Bantu language. Similarly, many Ndebele people in Zimbabwe would understand Shona, while not as many proportionate number of Shona people may understand Ndebele. Phonological diversity may be due to more exposure to other languages and not derivation of the language. Its possible that Kalanga was derived from Shona and that it later experienced a lot of exposure to other languages to which Shona was not exposed. For example, it could have been exposed to the Khoisan language.
How else could the Shona become the largest Bantu group in the World which has remained largely undisplaced geographically despite many historical migrations passing through them? It is most likely because
they built ancient cities and a collective memory and experience that has largely enabled them to remain undisplaced between Zambezi and Limpopo in the North and South and the Indian Ocean in the East and
and the western deserts despite huge migrations passing through this region. Mapungubwe is largely an empty site and yet it has attracted a large amount of attention than Great Zimbabwe, where one can actually see an ancient city with concrete evidence of Shona habitation in ancient times.
It is important to note also that the name Mapungubwe is a Shona name and absolutely not a Jewish name (the Lemba claim Jewish origin)!

I also wonder why it is so hard for the Lemba to claim that the Jews have Lemba origin instead of the reverse.