You are dense
Providing the information that this US court has requested involves someone in Ireland breaking Irish law.
Breaking the law is illegal.
Therefore this is an illegal data grab.
In addition, this isn't a valid search warrant. You can't search an Irish property with a US warrant. Well, you could, but someone could break your legs for your troubles and probably walk off scot free.
The other US companies are right to be scared. If I hold sensitive data on a service provided by an Australian subsidiary of a US company, and these shenanigans are allowed, than the US can seize my data at any time they wish without consulting an Australian court.
Naturally this isn't something I like the sound of; therefore I will not put my data at risk in this manner. Now, I might be a small drop in a large ocean, but these US companies are already looking at losing their foreign markets because of the NSA actions, and this is another nail in that coffin.