Oh yes, with all due respect, they are very very wrong. I realize that when I was having my colon issues, then ended up with proctitis, things down there in that department were hot, inflammed and mighty angry. However when the scope was inserted about 4 inches the doctor hit a sore spot. I am not even kidding when I tell you I flew forward so fast and sort of screamed in pain. I think I was sort of shocked because I don't usually react that way and can handle a lot. Again, I realize I had issues, but the point is, if there were not many nerve endings down there then I would not have felt the pain lke I did. And if you have ever had a condition such as post infectious colitis, then you would know you had nerve endings there.
I have seen people during light sedated colonoscopies and they moan out, yell out, or cry out multiple times during the session, so there have to be nerve endings there.