It's called scientism. It's their religion. It's became part of the identity of self. To attack it is to attack their own concept of self. Cognitive dissonance is painful. As most Democrats never mentality/psychologically matured past high school, they have no means of coping aside from crying or attacking.

Never forget, you're arguing with children trapped in an adult's body. A child who worships both the state's supreme authority and their false religion, as prescribed by that authority.

That brings up another point, they sure do love using race mixing as "proof" that "we're all exactly the same, race is only skin deep" whenever someone mentions how blacks are at best a sub-species of homo sapiens.

but coyotes and wolves are considered totally different species and can breed viable offspring.

Polar and Grizzly bears too.

Even the offspring of Lions and Tigers, previously thought to be sterile like Mules have now been show to be capable of creating viable offspring.

so with the "any animals that can breed are the same species" argument debunked what do we have left to categorize species?

appearance and physical morphology, genetics, and behavior. based on these criteria there at at minimum 3 different species groups of humanoid, Caucasians (Whites, Iranians, Arabs/North Africans, Indians), Sub-Saharan Africans (Ethiopians, Congolese/central Africans, West Africans, ect...) and Asians (Central Asians, East Asians, South East Asians, and Oceanian Asians). I'm unsure whether Amerindians should be included as a sub-species in Asians due to their siberian origins or set aside as an entirely different group. Australians abos I'm not sure whether to categorize at all, they're literally dumber than Africans.