Every wedding I've ever been to almost always involve all kinds of people who may not know the bride or groom well, but are related to the parents, business associates, what have you - it's normal to have a mixed crowd.
The "reformation" involved a "born again" component, so he would probably have been happier not having the issue even alluded to / mentioned at all; he was the black sheep of a big-into-Jesus family. My point was more that the best man tried to be funny by acknowledging his past sketchiness (by referring to having virtually no G-rated material) and fell flat on his face doing it, he embarrassed the guy and his new wife.
I suppose I should have said "don't reference the past if it's better for your brother that you don't". Sometimes trying to be funny with the best of intentions still winds up not working out. The guy clearly intended to get a laugh, not cricket chirping noises...but that was how it turned out.
I dunno, if shit went down the way you're saying it did, the crowd in your story sounds pretty insane. Unless the non-G rated material you're referring to is that he set old people on fire, I think the crowd should have chilled out.