Over the long haul of a 162 teams that's obviously almost always true, but in a shorter timeframe and the spotlight of the postseason things like intangibles and momentum start to play a bigger factor.
Not all managers and coaches are going to get along. Gibby wasn't universally liked either. I can't really comment on the later part of Gaston's managing career post 2004, I lost interest in baseball during that period. But didn't the teams in his second managing stint (along with the end of his original tenure) mostly lack the player personnel to be competitive (even the best manager can only do so much with a bad team). Anyway I wouldn't put the guy up there as an all-time great manager, but winning championships does count for something. My question was and remains, what is so great about Bobby Cox with his postseason record of 67W - 69L