Actually, no -- it's much easier (and far more fuzzy) than that.
Specifically, it is sinful to "be mean," which is probably best defined as saying "no" to somebody feels very strongly about something.
Note that this is not isolated to the Episcopal Church, nor even churches in general. It is, in fact, the moral standard by which the left operates in all facets of life.
That's why it is a mistake to treat these denominational church dust-ups as isolated events -- they're not. Rather, they're just particular examples of a far larger leftist political movement.
Uh-oh. Jesus is in BIG trouble.
Here's a scarier article:
http://www.virtueonline.org/portal/modules/news/article.php?storyid=4311
The Epicsopalian voted against affirming that Salvation is through Jesus alone.
Your implication is that there is a two way street. A Conservative saying NO to a leftist is sinful, and a Leftist saying NO to a Conservative is sinful. I really doubt that this is the case.