It is none of the umpire's business how you play the game, as long as it is legal.
You don't way what age level, but I assume fairly young. Since you say you "drafted" your team, I am assuming it is a rec league. Agressive base running in a rec league when you have a substantial lead will not likely make you a favorite with the other coaches. (But, as I said, it was none of the umpire's busines.)
The umpire should not be calling TIME while a play is in progress. ASA rules say this explicitly in Rule 10-8E. I would guess other rule books would have a similar rule under the "umpire guidelines" secton.
It is bordering on a violation of ethics for an umpire to suggest your team would have won if he had been calling the game - it could be interpreted as favortism.
Maybe this guy (28 walks in one game; 38 in another) is the umpire Coachtindell has been complaining about!
Anyway, what can you do? You may want to tell the umpire association's UIC and/or your league commissioner what you told us. Someone in authority over this umpire needs to talk with him.