I think the answer to that poll is either Hakeem or Tim Duncan - those men have a total of 6 NBA titles. Dirk has zero. Those two guys have better rebounding and assist stats than Dirk and their defensive stats are frighteningly good. Dirk simply is not in their class as a defender.
Hakeem's career steals plus blocks number is off the charts, but Duncan actually has a better overall defensive rating than Hakeem.
Here is an interesting fact - toss in KG to this group of three and you will see that statistically Kevin's numbers per game jut do not match up statistically. He is the 4th guy in the group statistically.
Now part of that is KG played for shitty teams when he was young and once he reached a good team he was not as good, but I think history will not treat Kevin as kindly as it treats Duncan and Hakeem (and Dirk if he gets a title).