3D printing is not plug-N-play. There are many aspects to producing a quality print, as we all know. As for me using and recommending American-made filament, it's a matter of confidence in the quality. It's knowing the specs and testing that went into manufacturing it and that the maufacturer is only a phone call away, if I have concerns. I can focus on other aspects when I produce a less-than-optimal (READ: crappy) print.
I don't have time to bounce questions about filament, off of the (typical) drop-shipper who also sells jewelry and shoes.
I know there are non-U.S. suppliers of quality filament; I happen to like U.S.-made filament.