. . . but rather the pop culture bleed that leads some people to apply it to non-D&D media as a universal framework. People do the same shit with the 3 x 3 alignment axis, which also bugs me.
"Gandalf is an angel, not a wiz-" "No, you shut up! Wizard doesn't mean that in Middle Earth."
"If some people are just born magic in Tory Wizard Land, they're really sorcer-" "No, you shut up! Wizard doesn't mean that in TERFlandia."
The whole problem only exists because TSR/WotC needed a name to stick on a guy who does magic slightly different from the other magic guys. It doesn't have anything to do with historical uses of the word.
The real difference between Wizard and Sorcerer? "Wizard" comes from Old English and literally translates to "wiseass" and "Sorcerer" comes from Latin by way of Old French and probably originally meant "fortune teller."