I do not see Ukraine quite as innocently as you do. They take all they can get without giving back and then expect the world to bail them out when they get in a pickle.
I think there is a lot of corruption and the citizens of Ukraine get shafted by everyone, not the least of which is their own leaders. But even they are not entirely innocent. They still do not know how to not be dependents. Oh they are learning to mouth off and talk big, but they fully expect other countries to fund and man their defense.
I do not think funding any part of this is what the U.S. should be doing. Neither do I think we should play world police there. Let the EU fund it since they are the ones involved. But that lily-livered bunch always wants to dump their messes on the U.S., too. The U.S. is in deep debt and needs to spend only where necessary. This ain’t it.