DRob was the starting C of the Spurs 1989-90 to 1995-96, 1997-98 to 2002-03, 13 seasons. Those 13 seasons San Antonio was
the best team in the league defensively at just 101.0 pts/100poss allowed. They allowed the lowest 2pt FG% (45.4%) - that's over 1034 games - the 2nd lowest 3pt FG% (33.6%), had the 3rd best defensive rebounding percentage (71.1%), yet were 2nd worst in the league in turnovers forced (just 15.4 opponent TO/100poss).
So the team was great defensively - for a
long time, 13 seasons - primarily because of the low 2pt FG% allowed (86% of the FGAs they faced were 2pters), and their very good defensive rebounding.
During that time DRob played 34124 minutes (no one else on the Spurs played more than 20700), close to 1/7 of the Spurs total minutes played (Duncan played just 1/2 that much, 17726 minutes). He had 7382 defensive rebounds (no one else on then team had even 4100), 2948 blocked shots (no one else even 1200), and was named to the all-defensive team 7 times.
Actually those 13 seasons DRob's 2948 blocks were 339 more than any other player
in the league, and his 7382 defensive rebounds the 2nd most among all players in the league.
So Robinson was - by far - the best defensive player on a team that over 13 seasons was the best defensive team in the league.
Mutumbo pretty easily. For those that saw both, not sure how this is a debate. Poll results are insanity.
Easily? It's a debate because you have absolutely no clue what you are talking about.
Two of the best defensive Cs ever in league history, but one's team had far more defensive success than the other.
Even without Duncan (the 7 years 1989-90 to 1995-96) DRob's Spurs allowed the 2nd lowest opponent 2pt FG% (46.7%) - that's over 574 games - with the 2nd best defensive rebounding percentage (70.3%), were still bad at forcing turnovers (3rd worst in the league at 15.3 opponent TO/100poss), and were still the 3rd best team defensively (103.4 pts/100poss allowed) in the league.