If you're the developer of a game played by millions and millions of people across the planet you should be professional enough to focus on the other faction as much as your own faction.
If a developer plays Horde and enjoys the Horde more than the Alliance that's ok but be professional enough to put the same effort into the other faction as you do your own. This is your product that you get paid to work on so pull up those pants and put it in the work, not just on your own side but on the other.
These jokes and quips just come off childish. If you can't be professional enough to put work into faction balance on the game you get paid to work on then maybe you shouldn't be working on an MMO.