You get what you pay for. If your league hires young, inexperienced umpires, why would your expectations of their abilities be any higher than that? That's just a reality of recreational ball that you have to live with- games played by young, inexperienced players will usually have young, inexperienced umpires.
An experienced umpire probably would have warned/ejected your coach for: 1) Being out of the dugout and behind the backstop, or; 2) Arguing balls and strikes with the "You got to call it both ways" comment.
The former is a standard rule that is easy to enforce. The latter is a common complaint, usually made by inexperienced coaches that don't know any better. It always bothers me to hear about an adult coach (who should know better) using such comments to intimidate a young, inexperienced umpire. It's no wonder that so many young umpires quit after a season or two.
I also have to wonder, if your pitchers weren't getting the borderline calls, why would they continue to throw the same pitch in the same location? Sounds like an issue with inexperienced coaching. Once you realize you're not getting that pitch, you have to adjust.
Does this sound a little harsh? Maybe it is. Would it soften the blow if I prefaced my comments by saying that I was, "Just venting"? I don't think it's really any more harsh than publicly ripping some teenaged umpire over a low-level rec league game on an internet discussion board.
I just get a little ticked whenever I hear, "The umpire lost the game for us", routine. We're getting a one-sided opinion- and a one-sided opinion by someone who obviously has an emotional stake in the outcome of the game, at that.
So, besides a few close pitch calls (which your pitchers apparently never adjusted to), I suppose nobody struck out, made an error or stranded a runner on base, and there weren't any wild pitches or passed balls or baserunning mistakes throughout the entire rest of the game?
Using the umpire as an excuse diminishes the efforts or your opponent and minimizes the shortcomings of your own team.