Don't be disingenuous. Its far from "just a press release"; its the official position of the government of the United States. There are many other instances where different parts of the government call it illegal.
It is just a press release and regardless, what any country’s official position is, is irrelevant. Legality generally doesn’t apply to international relations as each state makes their own determination on what does and doesn’t apply to them.
For example the current US ambassador to Israel just announced that France will be partitioned into two states, one for France and one for Palestine, France isn’t bound by that.
