What are all the people doing in the audience? They do nothing but get sloshed and make a racket. How do the players concentrate with all that gubbins going on?
Since almost all pro players have honed their craft in pubs, I imagine that the noise of inebriated people around them is perfectly natural, and they probably zone it out when they are throwing.
It's probably better that the spectators make noise all the time, rather than in snooker where it's deathly silent but a single cough can put a player off.