I don't think people were thinking of left-handed shooters when it comes to ambidextrous handles but rather more that it would be more ergonomic and easier to have it on the left side.None Issue solved by training . It the same way , for left hand writers, there is no left hand shooter in PLA , they are taught to use right hand instead.
For other applications, I don't think it is a major problem , standard issued AK also doesn't have a ambidextrous handle.
Also the gun in the photo is QJB-201/QJS-161 (the designation isn't clear right now) .It is a squad light machine gun , not a assault rifle.
It need to have a ambidextrous handle is even lower , it is mainly used with the bipod prone , and charged with the right hand since it need to be polled quite bit more force then a assault rifle.