>>847751
Episcopals have only been left leaning in the past 30-40 years.
As for the OP's question, it's just that many old (WASP) families were part of it. It's a whole network of connections that goes back far.
>>847752
>Episcopal are generally non evangelical and have not made significant inroads to poors and nonwhites in american history.
Methodists aren't Evangelicals either really, but they historically focused on the poor, starting with Wesley himself in England. Then moreso in America.
As an aside, some say without Wesley, England would have fallen to Revolution like France. But he came at a time that addressed working classes, built/encouraged more services for them. So by the time revolutionary talk started in Europe, it mostly fell on deaf ears in England.