The judge said that the warrant served on Microsoft is valid, meaning that Microsoft, which has control of the servers in Dublin, can be required to use its access to its own servers to turn over information within its control. Nothing Earth-shattering here.
Unless servers actually belong to a business entity registered in Ireland (Microsoft office there or whatever), which is subject to EU laws and regulations, not to US judge opinions and wisehs.
If server belongs to company registered in Ireland (regardless of who is the 'parent' company), they would likely be breaking EU laws and regulations if they would follow orders from US judge.
Do you have objections to Chinese judge ordering Huawei to disclose personal data of their US customers?
If you don't, I guess there is nothing to debate then.
I have problems with both, though.