Anyone disappointed should just boycott everything coming from the USA
This is the lazy and ultimately wrong way. Sure, it doesn't hurt, but its actual effect is not very powerful.
The better way to get back at USA is to start doing things better than they do. Stop fucking around and do stuff. We might be there in some limited areas, but in general the US rules over the world economically because they're good at making things.
Would be interesting to know if your attitude is a typical attitude in Europe. I would sell all my european funds and buy american ones to replace them if it is.