they do indeed sell buckfast behind the bar in the bernard shaw,but buckfast in ireland seems to have a totally different demographic - it is mainly drunk by clubbers and hippies,and isn't really that associated with rowdiness at all,drunken mayhem perhaps but not violence.
myself the one and only time i was absolutely out of control drunk was a result of buckfast,but that was numerous bottles and other stimulants consumed over the course of 40 hours or so with scant regard for my well being and no meals,other than that i've been drinking it for years with no ill effects,i don't even get a hangover from it.
also its slightly different over here,its thicker and more syrupy,sort of like calpol or something,in britain the consistency of it is much more like wine which in my opinion makes it taste horrible.