I can't help feeling that this thread is actually split between those who automatically think bees – busy, useful, even vital, to the future of the human race, appealing insects – and locusts – destructive, devastating, unappealing, horrendously noisy, interloping insects, harmful to the human food chain. Would we have had the same response to, say flock? Of course we would because some would think of flocks of free-flying birds searching for their summer or winter homes and other would have thought of silly sheep bred for slaughter. He could have used the word crowd but it wouldn't have implied the dynamic of these people in the current situation and mob, although really just a crowd, suggests some sort of aggression and political unacceptability. Using a collective term for a large number of people really doesn't negate a consideration for the individuals within a group – the latter was not what he talking about so far as I understand.