This is the real reason:
Material World: Greenland – A New Field for Capitalist Exploitation
https://www.wsws.org/en/articles/2024/12/24/ktyf-d24.html
World expansionism is a natural law of the capitalist economy, it is not because a president is crazy , and he is losing his mind, presidents can not control the market system
The US ruling class wants to take control of the Panama Canal but also the Chinese are building a mega port in Peru which might shorten the delivery of their commodities to Latin America and expand their market, and China is the second largest partner in the region and their market is around 489 billions dollars