Music is completely subjective. Best male vocalists based on what parameters? Those in our lifetime, in past generations, or total song production, number of covers, or only those with black hair? Just a point, and why only three? Here is my list: Dean Martin, Burton Cummings, Vic Damone, Frank Sinatra, Tony Bennett, Marc Jordan, Johnny Desmond, Andy Williams, Alan Jackson, Bob Jones....and those are only the ones that come to mind now.
Looking at Bob Dillon and Bruce Morrison, a couple of guys who actually couldn't sing at all but whose poetry, creativity, and the era they were in carried the day and their fame forward.
Elvis could sing pretty good. He used the pelvis outlandish bit to get famous. Do we separate raw talent from marketing or consider it all the same?