All modern business is built on trust, since Americans are keen on throwing that out the door now, every EU business is going to re-evaluate who to trust.
Which means, no longer trusting American.
Which means, no longer trusting American.
By wasting money you mean selling weapons and giving away old military equipment that it more expensive to destroy than to ship away?
Also, the conflict is in America's concern since the United States has pledged to guarantee Ukraine's security in the Budapest Memorandum of 1994. A pledge is a pledge, no matter if you like it or not.
But to your point, as a random European resident, it's not upsetting that the US is pulling back, it's upsetting that it's pulling back with so little regard for anything else. If this was the only thing, fine, i wouldn't agree but it's your call, but look at all the other stuff happening at the same time in your foreign policy and ask yourself why all those "wasteful" things existed in the first place.