What’s the problem? We took nationalist names (Mexico, Ontario) and used the hemisphere appropriate term. If anything we’re more culturally progressive for doing it.
Lake Ontario wasn't a "nationalist" name. It's an anglicised version of the Wyandot name for the lake. The Canadian province is named after the lake, not the other way around.
Don't be a ghoul.
Either way, America is more inclusive. Don’t be a ghoul