Exactly, either a domestic or international migrant. While right-wing ire is usually focused on international migrants, left-wing ire doesn't discriminate between domestic/international. It's build the wall rhetoric but oriented more towards localities as opposed to the US as a whole.
transplant isn't inherently pejorative. People who move cities will frequently refer to themselves by this moniker.
I've always literally never heard it used to refer to someone who migrated from another country. Only someone who moved domestically.