Rational: It’s funny you mention Taharas Hamishpachah. Dr. Elman holds that most of the Minhagim of Niddah are taken from the Zeroastrians. (He may not be wrong on that entirely and it’s hinted in the Gemara, but he takes his opinion way, way too far.)
Charlie: I have spoken to Dr. Elman personally on several occasions and have an extreme respect for his Torah knowledge. That is the only reason I don’t speak against him in sharper terms than “he probably crosses the line”. If anyone less knowledgeable than him would say the same things as he does I would call them an Apikores and walk away, no questions asked.