My experience is similar - maybe because I'm female and generally travel alone, I do find a group of drunk men far more intimidating than a group of drunk women. I don't dispute that hen parties can be messy, noisy, behave inappropriately. I hate having to travel near a hen party as in general their behaviour on trains is thoroughly antisocial but I've never felt personally threatened or scared by the experience. With drunk men, I feel far more anxious as I have experienced inappropriate comments and behaviour in the past (unwanted physical contact, sexual comments up to and including rape threats, suggestions that they'll follow me off the train, etc.). I'm fully aware that this is a minority of men (and maybe men have similar issues with crowds of drunk women). Just stating my personal experience.