By that method, "homophobe" would be one who fears mankind, not what it commonly means.
"homo" can be either "mankind" or "same" If it is taken to be "same" then it refers to "same sex" in the word "homophobe" and is inappropriately applied for political reasons. Very few people fear homosexuals ("same" sex affinity). Those that do or who have an uncontrollable violent reaction to the presence of a homosexual are "homophobic".