Indeed ! But as pointed by the sample I provided, you can use that word to refer to the act of grilling vegetables, so there is no point in being overly particular about the use of the word grillade. If a word was already reserved for the designation of grilled vegetables, on the model of bus/car or train/tramway (ie /within a city/ vs /between cities/), I'd accept your argument.

However what's discussed here is a case of legislators deciding what shape language should take, not usage !