Originally it just meant "this is really who it claims to be" to prevent fake accounts of high profile people from fooling users. Twitter themselves chose to make it political, and this mess is their own fault.
Not really. Lots of people who requested the checkmark and had valid credentials were denied the checkmark. If twitter gave you the checkmark, it meant you weren't a fake account *and* they had deemed you worthy in some way. Just because they kept their reasoning secret doesn't mean they weren't conferring extra status intentionally.