<I'm risking rocketmans wrath by posting this>
Of course men can be bullied. I regret that I didn't see what Cleo did, so can't comment on that, but as a general outlook I'd say that if Dirk was offended by her behaviour and said so she should have apologised.
I did see BB ask him if he wanted to make a formal complaint and him decline.
Nonetheless, you appear to be looking for intervention, for a nanny figure, or perhaps a headmaster, to instruct the contestants on how they should behave. Even if no formal complaint has been made.
I see no need for that. He's an adult playing a game, as she is, both in different ways seeking to avoid nomination by their fellow housemates and trying to appeal to the public. Just now I think he's rather isolated in the house but she's in a much more vulnerable position with the public. That's my guess anyway, but it might change when I see the show tonight.
"the fact is that the coven's plotting has been shown live", well yes, isn't that part of the reason the public is likely to vote one or more of them out?