The interweb disagrees with you.
“Technically, all tequila is mezcal. The term mezcal refers to spirits made from the agave plant, while tequila refers to a specific type of mezcal that can only be made from blue Weber agave in five Mexican states.”
This is not the case and any site that says it is is a long way out of date.
Here is the NOM for Mezcal and
here is the one for tequila. If you don't read Spanish there may be a Texan in the thread who will translate.
Or
this article or
this one summarizes in English.
Essentially, most all tequila is made in Jalisco and a spirit made in Jalisco can't be labeled Mezcal.
