**How are you so sure that these folks in India were not transplanted Israelites? **
This is the first time I have heard this? I bet you have some kind of a source and I just haven't looked for it yet.
Yup....it's called the Bible! [Amos 9:9] For, lo, I will command, and I will sift the house of Israel among all nations, like as corn is sifted in a sieve, yet shall not the least grain fall upon the earth.
And...a recent news item... Israelites in India ....from another respected source.