"B.C. - is it a..." joke

Here's a story I found this week in the Charleston [West Virginia] Gazette in a column by a man named Terry Marchal. He publishes humorous things that people send to him...
There was this very delicate, proper and elegant woman who was planning a family camping vacation in Florida. She wrote to a campground for a reservation.
This woman abhorred what campgrounds refer to as "pit toilets" (known in West Virginia as outhouses) and wanted to know if the area had bathhouses with flush toilets. She didn't want to write "toilet."
Campground guides and brochures use abbreviations for camping facilities and the woman remembered something about "B.C." which, she recalled, meant "bathroom commode." So, in her letter, she wanted to know if the camping facility had a B.C.
The campground owner was unfamiliar with B.C. He showed the letter to several people. Most were baffled. One knowledgeable camper, however, said he knew what it was. She was referring to a Baptist church. So the campground owner sent the following letter:
Dear Madam,
A B.C. is located 9 miles north of the campground and is capable of seating 250 people at one time. It is located in a beautiful pine grove and is opened on Sundays and Wednesdays.
It is a beautiful structure - red brick and well-kept. My daughter met her husband there.
The last time my wife and I went was six years ago, and it was so crowded we had to stand up the whole time.
It pains me very much not to be able to go more regularly, but is surely not due to lack of desire on my part. As we grow older, it seems to be more of an effort, particularly in the cold weather.
If you decide to come to our campground, perhaps I could go with you the first time you go, sit with you and introduce you to all the other folks. We are a friendly community.