That birds of a feather flock together is a law of human behaviour....the bloke will be co morbid disordered and combination of the clusters might apply....so will his mates be the same, this is ALWAYS the case and even more so with the lower IQ cohorts..regardless to get the metal of any individual just look at the personal quality of their 'friends' the lower the consciousness the stronger the need to associate only with those of the same or relatively lower consciousness.
The passengers shouldn't be held liable, to consider this as realistic is just another fascism..sure they all will be scum humans as a rule but there is no law against that not matter the IQ or type of any birds of a feather grouping.
