Unfit and Unsuitable are not synonyms.
Unfit is incapable. Unfit is not a judgment; unfit is a fact. You cannot force the fit.
Unsuitable is situational. Unsuitable is clothed in elitism. Unsuitable is condemnation. Any man can follow suit. All men can fit a suit.
Everyone wants to fit in.
I stood outside a shed and watched the subsets: a group gathered around the bonfire; a group gathered around the band. And I saw they saw their unfit.
Some men are unfit for friendship; no man is unsuitable for friendship.