Language is an inter-subjective tool for communication tool that perpetuates itself thatbks to people that use it. Redefining the words every time you use them is a waste of time, unless you're doing some academics work (which is not our  case I suppose). It's like if you were to redefine every postulate, axiom and theorem of mathematics every time you need to apply derivatives...you can do that, but good luck. It's a tradeoff between practicality and transmission of a message: in this context the "right" and "left" words communicate a broader gist, that's the important thing imo. 

 Language is evolving. Not I am changing the definition, society does. 
If you want to avoid misunderstanding, it is important to add precise references (Like in physics when we say „according to xy“) or explain the context, when using vague terms like left or right. There is no precise overall definition for them.