I don't know what the specifics of this case are.
I don't care about the Ryanair culture at this point or how the treatment of their passengers might have induced this behavior. Before the usual hysterics start as it always does when FR is mentioned, just spare a thought for the Cabin Crew.
They are the ones left to deal with a situation that no one should ever have to face. It's in these situations that they get crapped on from above. Young girls, maybe as young as 19 years of age dealing with packs of larger louts behaving like wild animals and a situation that developed into something similar to a spaghetti western or a bar brawl. Can you imagine how frightened they must have been?