In this context, a pronouncement like this from the “leader”, or even the dementia-riddled tribal figurehead, of the US could be disastrous. Regardless of his proclivity to write his name in water, or the general understanding that we’re dealing with someone who was always emotionally and intellectually stunted, the world could watch as China starts to unlock the deeper potential of space science, while the USA grows aggressive and grasping in a domain where there are as yet no people, and no rules. Even with Trump gone, what do you suppose a President Hegseth or Vance would do in cislunar space? “Claiming” Luna isn’t feasible, unless you try to shoot down any craft landing there, but what about the Lagrange 2 point or the geosynchronous belt above Earth?
When you consider how Musk, Bezos and the FCC cabal have effectively been squatting in Low Earth Orbit with Starlink and other satellite constellations - to the point of crowding out other users - I wouldn’t put any of this past the post-Trump USA.
Denying your opponent the use of space, be it Low Earth Orbit or points beyond in cislunar space, is hardly trivial. You would notice if the GPS, weather and communication functions of Earth’s satellite swarm were denied you. China and Russia understand this well, no matter how many people here may be stuck in their blinkered, reactionary opinion that “space is a waste of money”.