The problem here is not min/max itself, It's is when a game becomes less enjoyable because of it, in WoW you can see it as rerolling a class to get a better racial, or even playing a class that you dont like just because the numbers are higher.
Of course, this is a choice, you can just ignore it, but some people will think they are losing something and will have a question in mind: Are numbers > Fun ? And there is the main problem, no one should be forced to do a very drastical change just to get better numbers, like tranfering a guild to other faction to get better results, i mean, it's totally OK to have race differences for example, but it HAS to be balanced, you should not be force to play an Ogre Alchemist because you would be totally better than the Human Alchemist.
"Yes, you can be that, but if you go this way you will do the same things, except that it will be better."
It's probably the playerbase fault and the constant drive to get better, specially in online games. Games like Starcraft are generally very hard to play at its maximum and that can drive new players away from an good/fast online experience. But that's not bad if this is the objective of the game.
As long as min/max don't overcome the enjoyable I think it's fine and fun, it gives more depth to a game and also rewards more dedicated players, but, it's really importante that the DEVS balance it, even abusing of min/max the game should still be played the way it was made to be.