no such guitar controller has been commercially produced for left handed people but many creative left handed people have made or modified a right handed guitar controller to be left handed. playing a right handed guitar left handed is still easily achievable and is why no people bother to have a left handed specific controller.
the same way right handed people do but the strings are reversed and so is the guitar I'm left handed and I play "right handed" guitar. After all, it's my left hand doing all the hard work. Same way you play the right handed, except you strum with your left hand and use the fretboard with your right. I cant play a right handed guitar so good job on that.
Its because that is what is comfortable for you. I play the guitar left handed and write with left, but people can be ambidextrious (i cant spell...) and do both. That's why. above is true( also i have a theory that its because it's more difficult to hold in your left hand if you are right-handed) =-p