It is true that the Mar Thoma Church is a Reformed Eastern Orthodox Church, but the church is neither fully orthodox neither protestant. Personally, I tell my friends who are not from the St. Thomas tradition that the church is a Reformed Oriental Orthodox Church. It is more technical to put it in that terms becuase the Mar Thoma Church reformed from the Oriental Orthodox Communion of Church, and that the Eastern Orthodox church are mostly composed of the Orthodox Churches in Russia and Eastern Europe. The Mar Thoma Church is not fully protestant because the Church never came out of the Roman Catholic Church, and that the term "protestant" should belong to those who "protested" againist the Catholic church (Lutheran etc.). The church is not also fully orthodox. It may be orthodox in tradition, but not in specfic terms. But to answer your question, the reason why many people refer the Mar Thoma Church as a "Reformed Eastern Orthodox Church" is because it probably formed with the other churches out of the Kerala Churches. Some people (espically in America) have no understanding on the term on Reformed Oriental Orthodox. Majority of the population is either Protestant or Catholic w. a minorty of Orthodox, Mar Thoma, CSI etc. Only people within our St. Thomas tradition would knoe more about the stance on the Church. The Mar Thoma Church is in full communion with the Anglican Church, that makes it not orthodox, but it is neither Protestant because of its strong Orthodox roots. Besides that I'm proud to be a Marthomite and my churches heiterage, with a blend of east and west this makes our church different from all the others, but it doesn't matter on what the outer view on the church is, but to proclaim that all christians belive in one Holy, catholic and Apostical Church, and that Jesus is our savior!

Note: Please don't take this view as fact, but is a personal view on the church.