Well, I guess if Ukraine cedes eastern Ukraine to Russia and if Russia doesn’t want to seize any more of Ukraine than it already has, you would have a point. But at this point, Ukraine does not seem willing to give more territory to Russia, and there is no definite point at which Ukraine knows Russia will stop seizing territory.
If the U.S. gives military hardware, boots, socks, MREs, etc to Ukraine, then possibly Ukraine will be in a better position to defend itself against Russian aggression. It hardly seems to me that simply rewarding an aggressor with inaction is an appropriate policy, particularly since we don’t know that Ukraine will acquiesce in Russian seizure of more of its territory even without American aid.