I have always noticed from a young age that Americans appear obsessed with race...

Indeed. But there is a reason for that - they have this large black population that are largely descended from a transplanted population, and that population's history and culture is uniquely American. They were, as a policy, decoupled from the culture of the countries they were brought from. That makes American's black population a form of diaspora, with their own unique culture.

American's "race" issue is really about the collision between the three groups that combined to form America - the indigenous population, the settlers, and the settlers' slaves.

They view that 3-way collision in terms of "race", approximate that by skin colour, and then nonsensically reassign the American historical roles to people with the same skin colours in another country. Which is just dumb.

The ending of that response to that Harpers open letter was a gob-smacking example of this American genre:

The intellectual freedom of cis white intellectuals has never been under threat en masse, especially when compared to how writers from marginalized groups have been treated for generations. In fact, they have never faced serious consequences — only momentary discomfort.

PS, recommended if you haven't seen it - Bret Weinstein's recent round table with a bunch of black writers and academics. More sense than you'll hear from any of the Woke crowd.