It’s right handed. Get over it. It is an arbitrary decision, but so what? Everyone has their own preference for how they visualise things (I for example interpret +z as forwards/into the screen, and +y is up, and don’t really care about x), in the same way that everyone visualises the flow of time differently. The maths is no easier or harder either way, but it’s a real pain to convert between them when people make different assumptions. DirectX doesn’t insist on left handed (no matter what anyone has told you – it provides left and right handed versions of all the view/projection functions that care), OpenGL assumes right handed, all the big modelling tools use right-handed. The majority have spoken already on this, but every single developer that chooses to buck the trend makes the rest of our lives more painful.
And if I ever have to debug another handed-ness related problem, I think I’m going to cut off my right hand and replace it with a sharpened set of axes, then go round visiting all the games studios in the land, slashing and gouging all those who want to argue about it.