If boat trips from a few hundred years ago are not a claim of ownership, then why should this just apply for Denmark in Greenland, and not also for the European colonizers in North America?
The United States is expected to focus heavily on maintaining dominance in the Americas, while still regarding China as a major strategic competitor in the Asia-Pacific.
Trump, grandson of a German immigrant, is particularly peeved at an independent South Africa, which was the worst example of a Western supremacist-cum-colonial mindset.
What perhaps remains unresolved, is how long the American electorate will allow Trump to reduce their country into a paranoia state, an empire of appalling tantrums and ragtag diplomacy.