I didn’t know you could “resign” from a church unless you were on staff.
I resigned from the vestry of a Episcopalian church. Priest was going to teach AIDs stuff to little kids. I said what are you going to teach them? He said that God was not punishing gays. I said how would you know.
One can “resign” one’s membership in any organization which recognizes formal membership status. Plenty of politicians have resigned their memberships in “no blacks” or “no Jews” country clubs.