I take a narrow view of Christianity, too. And of the defintion of an evangelical church. As a mainline church, the ECLA does not meet the criteria that I believe are the correct ones.
What I’m saying is that the ELCA has been an established Christian Lutheran denomination for decades. And, it is the largest Lutheran denomination. That’s mainline.
The fact they’ve fallen in their beliefs and practices makes them unfit in God’s eyes, and the eyes of those such as us who follow God’s Word. But they can still be classified as a mainline denomination. They just ain’t Christian anymore...