I think the reason that many diehard Chic fans are so shocked is that they really heard Bob riled up last night on the show. He was angry at some points, obviously offended, and you could tell he was embarassed by the "puppet" comments made by Lee.
If there was no truth whatsoever in anything Lee said, it would have been a very calm discussion. If Lee had called and said Bob had an ugly bald head, Bob would have calmly replied that he had a beautiful head of hair, and there wouldn't have been an escalation of words. Instead, lee's words seemed to have at least a little truth, as Bob got shaken pretty quickly and never regained his composure.