He's not.
It's not like anyone was writing Kobe into 3rd. You had 101 players who didn't write Kobe's name at all, and then 7 players who were ridiculous enough to put Kobe over Bron and MJ and thus shouldn't be trusted. Those 7 players who didn't put MJ OR Bron in the #1 slot aren't gonna be choosing the top-5 for the other 101.
It's like a poll of greatest presidents where 95% of the votes were split between Abraham Lincoln and FDR, and the other 5% went to Trump. That doesn't prove Trump is the 3rd best president, it just shows a handful of people in any poll can't be trusted to make a rational choice.