Why? They have a terrible economy and dire needs at home. Neither country had threatened Ukraine. They were propping up a US government adventure that most US citizens don't support.
What this means in Ukraine is that training for that war is yet another source of residents who can fight a war. Why does the US want to stir up that hornet's nest?
It helps to understand what good comes out of those situations. Working with other countries greatly helps at other times such as when natural disasters result in several countries providing assistance. The Ukrainian flag ship took part in a NATO exercise.
The international group that consisted of naval ships from several nations virtually stopped Somali piracy. The Ukrainian officers and men that worked along side us undoubtedly not only provided insight into the Ukrainian military but also provided contacts for the future.
I wouldn’t be surprised if some of the members of our military have more insight from personal contacts in Ukraine than the White House.