Separating men and women in certain physical sports for safety and fairness is founded in reality and fact. Separating transgender women from cisgender women has no such foundation, and in fact the research directly disagrees with it. There is a minor difference between cisgender men and transgender men in terms of physical performance.
Your views are transphobic because you share and propagate disinformation about transgender people while, if this conversation is anything to go by, willingly choosing not to educate yourself on what the facts are.
Me pointing out that you are factually incorrect is not "unproductive" unless you as an individual refuse to educate yourself on what the facts are. I didn't call you a transphobe, I never said anything about you. I never labelled you. I told you that you were wrong. Perhaps you should look inward if you consider it "echo chambery" and "extremism" when you are told by a transgender woman that you are sharing harmful views about transgender people.

Heck yeah