OP's article doesn't link the opinion. After several fruitless searches I finally found it on the ACLU website.

Read the opinion once and here's a hot take plus a little red meat for folks opposed to an activist judiciary.

TL;DR - The President must dance around before the court like a marionette before exercising his statutory authority to limit entry of aliens into the United States.

Judge Watson's essential finding is this:

"The actions taken by the President in the challenged sections of EO-3 require him to “first make sufficient findings that the entry of nationals from the six designated countries . . . would be detrimental to the interests of the United States.”Hawaii, 859 F.3d at 776. Because the President has not satisfied this precondition in the manner described by the Ninth Circuit before exercising his delegated authority, Plaintiffs have demonstrated a likelihood of success on the merits of their claim that the President exceeded his authority under Sections 1182(f) and 1185(a)."

The EO-3 document itself lists various finding upon which the executive order is based. Judge Watson finds these 'findings' to be insufficient because they have not yet been proved in his own court. In order to pass constitutional muster Judge Watson must be personally be satisfied that The President has found that limiting entry of aliens into the United States is detrimental to our national security interest.

Citing heavily to supportive 9th circuit opinion Judge Watson implies that the term "finds" means only objectively verifiable and certain fact based conclusions. Like science. That in order to exercise his statutory authority The President must first make a case to the court for authority to exercise his statutory authority to limit the entry of aliens.

Now we'll have a footnote of Federal jurisprudence about what the definition of 'finds' means all while a District Court judge from Hawaii personally manages national immigration policy via a temporary injunction.

Also, here is dictionary definition of "finds": LINK

Which includes a number of definitions far less stringent than bearing the burden of proof to satisfy another.

Note: I'm not against Judge Watson's decision because I don't like the result.