There is no way to control dual citizenship. Drop that as a condition to anything. Other countries deserve the same autonomy we wish for ourselves. And a country has the right to grant citizenship as THAT COUNTRY WISHES. So you can’t punish American citizens who are handed citizenship elsewhere.
No one in a foreign land claiming foreign citizenship should be voting in US elections.
US citizenship can indeed be stripped from someone. One reason is accepting citizenship of another country. The USA does not have to accept a dual citizenship.