The bottom line as to why we are not helping Ukraine is: The U.S. and NATO are cowards and are afraid to face Russia.

If the USA and NATO militarily help Ukraine directly, then literally everyone is part of NATO, even non-members. That being said, the USA and NATO are indirectly supplying military equipment, money, and training which is no small gift of support. And, unlike Afghanistan, the Ukrainians are valiantly stepping up to fight their battle with those trying to occupy their homeland.