Something is better than nothing. besides it was the Ukrainians asking for them.The issue with the Australian helicopters keeps popping up - I get it that people want to get equipment to Ukraine, but they need field ready machines that can be put to work ASAP.
Even if the U.S. were to provide UH-60's to Ukraine, there would be training both with pilots and ground crew plus logistics for parts and such - all of which would create downtime and a lag between acquisition and deployment.