Unfortunately most people are of the 'lets go to the pub to get locked' mentality, and despite paying lipservice to the responsible drinking lark, most vintners are only to happy to have these beer swilling fish-like punters consuming vast quantities of alcohol, as it keeps the profits up, and the place in business. Loud music attracts this species of drinker as it gives them a chance to dance off some of the sugar-energy gained from drinking loads of sugar-loaded high-alcohol drinks. It also drowns out the drunken warblings, making the chance of actually remembering last night's conquests' name even more remote, (which is usually no bad thing).
Us here on this forum being a different breed of drinker, and the majority of us probably in the latter half of the 20-40 age group, tend to eschew this sort of bothersome noise, as it gets in the way of a good chat, and drunken dancing people tend to spill drink on us. Unfortunately, without these fish, pubs wouldn't stay open and we wouldn't be able to drink our nice beer, so in my mind it's a necessary evil...