It really is possible to be attracted to someone and accept that the other person isn't attracted back and still be nonromantic friends. I have done it, and I still have those friendships many years later.
So I think that there needs to be more advice on how to do this, as I've rarely encountered someone who's successfully navigated it as you have. Maybe a separate post on how to do it? But anyways, should people want to pursue that option, I think it's something that the individual needs to assess based on the strength of their feelings. If they are not emotionally ready for this kind of change (and from what I've seen a lot, maybe most, cis-straight men aren't), then I think not seeing the person anymore might be the better option. Otherwise if they really want to try to make a friendship work (and actually try to be friends and not try to "get in" later) then I guess your advice would be helpful.
I think it's both. Just like any other issue that socialists talk about, like racism, sexism, classism, etc. They can all be "dealt with" on an interpersonal level, but ultimately there needs to be a societal change.