I have no problem with Gates over Witten. The guy is good. The main reason he gets the nod is because football is about the fantasy points and Gates provides that more than Witten. Witten is great and does more as a blocker, but Gates is no slouch. I wouldn't trade Witten for Gates, but I also would not complain if Gates had been a Cowboy.
This partial list of guys does not list what team they made. It is possible that Gates is on the second team of the all-decade team. Gonzales is not playing in this years pro-bowl, so he is not amongst the 12 players participating who made the all-decade team. It is likely that Gonzales is the first team all-decade tight end. He should be. He played the entire decade where as Gates started his career in 2003.
For the decade:
Gonzales
831 receptions
9969 yards
12.00 avg
67 TDs
Gates
479 receptions
6223 yards
13.00 avg
59 TDs
Witten
523 receptions
5965 yards
11.41 avg
27 TDs