Yes, but he was in a sticky situation.
Of his own devising.
So in a situation where the USA might become actively involved earlier it would be in the interest of Eire to suggest that while they could not for obvious historical reasons agree to British forces, there are these perfectly good ports that could be used by fellow neutrals to ensure the "safety of trade" and if that led to trouble from the Continent....
In the previous paragraph you mention how US forces in Ulster were equally hostile to Ireland and in the very next paragraph you suggest it would be in the best interests of Ireland to allow the US to use the Treaty Ports. Huh?
Then, you have the US involved in the war earlier and Ireland allowing the ports to be used by the US as a
fellow neutral. Double huh?
Leaving aside the illogical explanations of your idea, any chance of any of this happening requires the bastard son of the Cuban Juan Vivion de Valero not to be the
de facto dictator of Ireland. As long as "Eamon" is in control, his overwhelming spite towards the nation of his birth and his near psychotic need to prove himself as a half Cuban and wholly American bastard to be more Irish than the real Irish mean that no one is getting anywhere near the Treaty Ports.
Germany could invade and "Eamon" could be on his knees with a Gestapo Luger pressed against his skull and the SOB would still be nattering on about Irish neutrality and sovereignty.
"Eamon" has to go, one way or another.