No different then saying speak America when you are speaking English...
there's an old saying that the only thing that separates the English and the Americans is a common language
IF you know the Spanish they speak in Mexico vs the Spanish they speak in the the rest of the Hispanic world it a far wider gap.
I know someone that spoke fluent Castilian Spanish and they could not understand a word a Mexican said when they finally picked it up they said it sounded like someone from the speaking arcane English that was from the deep south.
I myself grew up in the area of southern California that was 98% Mexican...I can't speak it but I can sure as heck understand quite a bit.... when I went to Buenos Aires I couldn't understand a word of the Spanish spoken down there it sounded completely different it sounded like Italian
There might be a reason for that. Did you know that there are over 40 spoken languages in Argentina? Yessir.... sho ‘nuff. If you don’t believe me, do a Google search.