Postscript on Exclusion
Paul Helm dropped me a note to comment that, although it is true that we live in a world which fears exclusion, there are still many socially acceptable voluntary organization which do exclude people: political parties, for example.
This is a good point. I would respond by saying that a full account of the unacceptability of church discipline, theological and ethical, in today’s society would clearly need to take into account not simply the fact that it involves exclusion but also the specific reasons for such. In the eyes of the world, for example discipline for adultery or for denial of the resurrection would seem to be self-righteously countercultural in the first instance and somewhat pedantic in the second.
Further, the traditional image of the church and much of the rhetoric of the church is that of inclusion. Come all you who are burdened etc. Thus, there is a dramatic dissonance between the public perception of what the church seems to be saying she is and what, by excluding certain types of people, she actually is.
Finally, we might add that the failure over many generations of the church to implement proper discipline has left even those within the visible church somewhat confused as to who she is, what she should believe and what behaviors she should tolerate. When the question, Who owns the church? (or more likely, Who owns this particular congregation/denomination?) has been made practically unclear over time, then the general cultural fear of excluding people combines with dissonant rhetoric and ecclesiastical chaos to create significant unpleasantness and further confusion.