It's not about being adversaries, he's just saying that he wants Europe to put more money into space R&D, not to lack too far behind the others. That's a good thing for everyone. And besides the european space agency is largely involved in the Artemis program and provided instruments for the JWST.

Just because the US is the big player doesn't mean its allies should stop all effort. Imagine if the US was like "ok the Japanese make reliable cars, we are allies, let's stop developing cars." That would be weird...