The conversation among we soldiers of the time was WHY? He could have accepted service, he could have been assigned to Special Services and even continued to fight.
I'm not sure his actions were self-centered as much as a protest of the way blacks were treated differently than whites. This was still the case in the sixties.
BTW: I do respect Ali more than Kerry. Kerry insulted the integrady of 3 million veterans who served honorably in Vietnam. There may have bee some atrocities and some drug use but it was not universal as he said.