There are many ways to answer this. Here is a high level explanation of why we are in disagreement. Instead of explaining 'How' and getting bogged down in the details and worse, trapped by semantics, I shall explain 'Why' I think we differ. Then if you want to get into the specifics we can.

I used to be a Creationist, how the political ideology of Progression thinks about biology is very similar to how Creationists have thought about biological evolution down through the last two centuries.

While both camps see each other as being extraordinarily different, this is not compelling evidence that they aren't related, note the conflict between Shia and Sunni. They see each as being oppositional... Similarly Progressivism and Creationism come from the same source. If you trace back the history of ideas to ye olde England and Germany this becomes startlingly obvious. It is not a coincidence that the phrase 'social justice' is Catholic in origin.

Why this matters is that when Darwin set off his Atom Bomb concerning the Origin of Species, he immediately ran into direct conflict with the Church because the implications of evolution theory contradicted the account of life being formed in Genesis.

Today Darwin's ideas have won out over Christianity. Most Christians believe in evolution theory, and they take the first book of the Bible as not being a literal account of reality. In my opinion this ultimately neutered the political legitimacy of Christianity.

However a descendant of Christianity, Progressivism, continues to not believe in Evolution. Unlike Christianity, it has managed to exert enormous political influence through the education system, especially the universities. It is what has tabooed discussion of human speciation.

This is less than obvious because most students would initially deny that they disbelieve Evolution theory. Then, as it moves further up against their taboos, red lights begin to flash and they begin exhibiting failures of imagination.

There are students that;

- Believe evolution explains the animal/plant kingdoms but not that of humans "there hasn't been enough time for human evolution" (christian variant: humans are special).

- Believe evolution explains human evolution in the past but not the present.

- Believe evolution explains human evolution below the neck only. Here the brain is immutable but obvious physiological changes are fine.

- Believe evolution explains the development of the human brain but insist that nonetheless human speciation is impossible (christian variant: 'microevolution' i.e. small changes up to a limit - The reason for the constrained scope is never explained, only assumed).

None of them want to acknowledge that if evolution is real then humans evolve, and if humans evolve, then logically there could be evidence for different groups of humans. If such evidence existed for the beginning of human speciation the strongest evidence would be found in human population groups which have been separated for the longest period of time e.g. 100,000 years.

As you know science is very dependent on the ability to replicate experiments and make predictions. This is why in universities in the West, this subject is so tabooed there are few scientists willing to stick their necks out by doing those experiments. One of the men who discovered DNA, James Watson, is blacklisted because of some off the cuff remarks about race. If a bollocking can happen to somebody who made one of the most important discoveries in biology, it can sure happen to a less prestigious scientist. It is a tabooed subject because Progressivism is founded on theological roots i.e. the premise of their beliefs was never rational to begin with. The Chinese, who have no such taboo, Christian or Progressive, are making huge strides in biological science because the Progressivism meme is not strong in China.

This documentary 'DNA Dreams' is worth watching to fully appreciate this.

https://www.youtube.com/watch?v=1dVv5RMwzuo