On a chart section spanning around 5 million years, are you asking about the millions of years where there was “all this diversity and branching” as contrasted with the last ten thousand years or so where there is less observed branching?
Around 15 branches in 5,000,000 years and 0 in the last 10,000 years seems more likely statistical than ideological to me.
I don't think anyone can look at the incredible diversity of humans we have now and say they're all the same species, while looking at birds or other animals and say they deserve to all be different species. One of those trains of thought are wrong, and humans seem to be the outlier.
That said, I don't want to be the one to have to tell people they're another race. I think calling all humans the same race simplifies a lot of life, and there's no reason we can't treat ourselves differently.
I feel like you're conflating race/ethnicity with species when the two are completely separate concepts. There's a great amount of diversity between dog breeds, including wolves, but little disagreement that they are the same species. Variation between members of a certain species is expected
Are you not aware of the multiple genetic bottlenecks homo sapiens have gone through?