They didn't do anything special for "Lake America". Google's long standing maps policy is to show people the names that their government says they have. As soon as that name showed up in the US government's database it showed up for people in the US on Google Maps.
In Canada it shows up as "Lake Ontario" because that's what their government says it is. In the rest of the world it gets both names because the two governments whose territories it is in call it two different names.
In Canada it shows up as "Lake Ontario" because that's what their government says it is. In the rest of the world it gets both names because the two governments whose territories it is in call it two different names.