Then you take responsibility when this guy or anyone new that you give this advice to, pisses off the wrong person with their flag and finds their account useless.  And that's up to you. 
As for myself, I will continue to tell people that it's a terrible way to make friends, that it's actually a great way to make enemies. If you don't think that people should use restraint when it comes to flags, then either you haven't been paying attention to what happens when people don't, or you enjoy the warzone.  Flagging leads to more flagging and bad feelings on all sides. Maybe it shouldn't, but that's just the way it is.

I don't know how she could have more carefully expressed her point, which is quite true.  

I suppose I can understand your getting his back, and I admire that of you, BTW, as you felt he was being browbeaten and threatened.  

I think he ignored the voluminous evidence they provided - he simply brushed it aside - and used flags, which no one did to him.  My own interjection wasn't a threat, but considering how being piled on by multiple voices might be intimidating in itself, I can concede how you might interpret that as browbeating.

I disagree with that interpretation, and took offense at his characterization of their concerns as dangers to the public.  Plus, he was flagging, and I consider that rude, as well as foolish, given he flagged a whale, because downvotes on Steemit take money from the victims, rather than simply express opinion, like on Fakebook.