Nah, you're argument is not valid here. How on earth was Valencia getting games at RB ahead of him as well? And I'm sure Moyes would prefer someone at RB who is actually delivering good performances, rather than giving games to Smalling and seeing him perform woefully.
So whats your argument? Moyes thought he was the 10th best right back and 3rd best left back after Buttner because Buttner is more talented?
The reason for Fabio not getting games at right back has no bearing on the fact he could (and should) have got games at left back because he's a
miles better player than Buttner who did get games. The only "advantage" Buttner has is he's left footed. Or are you suggesting he's a better player than Fabio?
Fabio didnt get games on the right to give more games to other players, whether they were Jones, Smalling or Valencia. It doesn't matter. The point is that all of these players getting games means it keeps them happy. He didn't care about Fabio being happy on the flipside because he valued those other players and obviously, theres no madness involved in preferring to keep Smalling, Jones and even Valencia happy over Fabio. They are all good players on their day and you could definitely make the argument they are simply better than Fabio.
Buttner on the other hand is clearly not better and not worth keeping happy instead of Fabio. There is no sensible argument for that. He is however left footed which is the explaination