I think that it's entirely up to Mexico to decide who can vote in their elections. If Mexico wants to allow US citizens to vote in their elections, it's no skin off my nose.
I also think it's imperative that we prevent non-citizens from voting in our elections. With motor-voter and all the document fraud going on, though, I'm afraid that's just not happening.
It is skin off of MY nose when Mexican Nationals try to indfluence the political leadership of MY country while still pledging allegiance to their HOMELAND.