Matt: Note to self - take this tourney off your bucket list 
Umpires assigned to 14U travel tournament games are certainly not at the level of quite a few on this board, so in the end it's a learning experience that you get to pay for. Quite a few "veteran" umps don't want or like these kinds of tournies - too many "know it all" coaches and parents, games last way too long, and the pay is below what they usually get. Not saying that's your perspective, but as long as you set your expectations going in, then you can just focus on the coaching and have your players focus on the playing (and your parents on the cheering of the team).... Hopefully you didn't "blame the umps" for the losses in your talk with the team... I'm sure a lot of veterans can agree that it's very easy to recognize the team with the coaches (and players) that aren't trying to (micro)manage the officiating aspect of the game too.
I never tell the team umpires "cost us a game." In fact, when I talk to my team after games like this the discussion revolves around what we could have done differently, so that we weren't in a position to have a call "hurt" us. I am not one of those coaches who treats baseball like life or death... I try to use the lessons baseball imparts to improve lives. Things like learning how to compete, and what it takes (mentally) to come out on top of the competition; life's not always fair, and how you deal with the adversity often is what determines true success (not necessarily the trophy).
I don't like to be involved in the officiating aspect of the game when I'm coaching, but I completely get what you're saying. More often than not, the only thing I say to umpires is "Thanks!" and "Good game, blue!" I really try to let them call the game, while I coach the game, the kids play the game and our parents cheer our team. Ours is kind of a unique team, we call it our "Baseball Family" and that's really how all 12 of our players and their parents approach our brand of baseball. It has worked well for us... we're not always the top team in the leagues (or tourneys), but we're always in the top 5 or 6.
Thanks for sharing your wisdom and perspectives John! I appreciate the words!