At first I thought this was just an example of Itanglese/Anglitaliano, but it seems this word is known in a few European languages and there are even English speakers who use it in this sense. It has also taken over as the main meaning on Wikipedia.
It seems to be one of those buzzwords favoured by ‘experts’ in some new, often self-invented, field. Not to suggest that they might not be doing something useful, but the obsession with creating your own niche term is a rather sad and predictable.
It seems to have been taken over from the biological sense where groups of animals take part in collective aggression, usually against a predator, but other species can be the target too. Birds are well known for this behaviour: e.g. both Indian mynas and (native) noisy miners will drive smaller birds out of nesting hollows.
So now you know. If you’re driven out of your workplace by a group effort of harassment (like Checco in Quo Vado?) it’s not bullying, it’s mobbing…apparently.