Maybe the problem is that they don't know what tantra is or WHY (there's that word) that you think it's important.

I would tell them about your whole progression of getting re-directed further and further from actual history, and that what you want to do is to increase the history known about the subject, rather than trying to answer a question that, in the context of the religion and those who study it, has no meaning...and would be speculative fiction at best.

They might understand that.