I think talking to the umpires after the game is perfectly fine however I have always used the cliché method for it to be effective...
- "Nice game blue"
- "Way to keep the game moving blue"
- "Hot day blue...you have enough water?
I have been around umpires for 45 years and "almost" (because I don't believe in absolutes in baseball) all know when they have made a questionable call or a call one group of fans vigorously disagreed with. Rubbing their nose in it only causes a bad association and you will see the same umpires over and over again through the years. Because they know they have made a questionable call they tend to respond defensively if approached in anger or with a suggestion that they need to read the rule book but don't confuse defensiveness with arrogance even if the response the umpire gave could easily be interpreted that way.
Over time teams that have parents or coaches that consistently complain about calls (not the groan that goes up when the call is made, that is expected, but the incessant "Missing a good game blue!", "Want me to read you the rule book blue?", "First game huh blue?") will find the umpires less willing to consult their partner which is usually the only way a call can be changed during a game. No umpire will say..."Oh my gosh!!! you people who are screaming and taunting me are right... I need to change my call"
What coaches want, if they have a valid rule based argument, is that the umpire will call time out, have a conversation with his partner and then make the definitive call. I usually begin that conversation not with a complaint about the call but with. "From where I was I am not sure I was able to see what you did, could you check with your partner to see if he had a perspective on that?" I bet 95% have consulted maybe 25% have gone my way...sure beats 100% going against
IMO the adage "If you don't have anything good to say don't say anything at all" is appropriate when applied to all umpires