I try not to judge anyone who stays in a liberal denomination on the basis that the local congregation "isn't like that!"
The problem for many people caught up in that kind of situation is that to belong to an affiliated congregation or parish, you have to help finance the national church's errors and you subject yourself to all the clap-trap that comes to you in the church's national publications, national convention resolutions, communications, etc. Plus everything that your neighbor reads about the national organization and assumes, logically enough, that it applies to the local unit.
The Episcopal Church provides possibly the classic example, but the ELCA and, more recently, the Presbyterian Church USA do also. Even if the individual does a good job of putting most of that out of his mind, there are still plenty of occasions in which something outrageous coming down from the national church has to be dealt with mentally. Obviously, a lot of people find that wearisome and a distraction, to say the least.