Left and right refers to where the Girondins and the Montagnards/Jacobins sat in the French revolutionary assembly. We’ve bastardized this into imaginary delineations of political positioning and for some reason we keep bolting on arbitrary positions as Girondin or Jacobin.

I don’t care what textbook you are looking at, I’m looking at (or maybe writing) a different one. Left and right do not actually “mean things” if you intend for “meaning” to be universally or even widely agreed upon. I suppose for you “meaning” may only be relevant if a certain group or class agrees upon the meaning, but the rest of us will continue to say and believe what we want!