Uh, American certainly isn't the only country that grants non-resident expats voting rights. My Mom is able to vote in Mexican elections and the last time she lived in Mexico was in 1992. Considering that she sends remittances to family members, owns a house in Mexico, paid taxes for quite a while and is entitled to her public pension, she ought to be entitled to vote in Mexican elections.
I'll note that most migrant-sending countries grant non-resident expats voting rights and that this is for a reason. Those who emigrate elsewhere are never fully removed from the communities and families of their country of origin. They usually have a stake in their former home. The idea that someone has to physically live somewhere in order to participate in the democratic process is far-fetched garbage that only a juvenile fool who's detached from the realities of adulthood would propagate.
The US isn't really a "migrant sending" country overall, though.
Pretty much all Americans who live abroad full-time are wealthy, highly skilled workers employed by multinational corporations. You don't have blue-collar Americans going to do entry-level work in Europe or Asia and wiring money back home to the folks in Kentucky.
The big difference is that if you're an American and live elsewhere, you made a conscious choice to do so. You weren't emigrating to support your poor, starving family or flee political or religious persecution. Most American ex-pats are members of the "global elite" who pretty much already have likeminded elected officials in any country they go to whether they can vote or not.
