My personal criteria for defining "one hit wonder" is far different. To be honest I have no concept of where a song "charted". But rather for me "OHW" is defined as a song that got major airplay, that I heard daily on the radio and then at some point the band/artist who recorded it simply disappeared and were never heard from again...
So that's why imho anybody who considers either Amie or especially FWIW a "one hit wonder" is more of a casual listener than someone who I believe takes musically seriously. I mean I don't see how anyone who is inducted into not only the RRHOF (twice for Stills/Young) but also the Songwriters Hall of Fame could even be considered by any serious music fan as a "1 hit wonder"
Of course that's my music snobbery shining thru. But various people have interests in various fields and I don't apologize for my appreciation of music the past 70+ yrs, just like I don't try to pretend I know anything about fields I could best be described as a "casual observer" of...
None of these songs are "hits", but their contribution to future generations of musicians are immense
Seriously, how old was Neil when he wrote this?
Or Steve when he first started writing songs about Judy?
And a song which unlike FWIW, Stills actually wrote about Vietnam. Beautiful way of highlighting the moral dilemma faced by draftees who had to flee to escape the "government madness" of being sent to fight in an undeclared war.