I've played many sports over the years and never have I wanted anyone to be quiet whilst I play. In fact, the more noise (support) the better as it increases the adrenalin. I am very good at focusing on the job in hand and can usually block out most things around me. I do think pros are simply finding excuses for when something goes wrong, someone to blame.
I have a couple of examples too.
1) I know a professional soccer player here in the UK who played soccer in the early 70's. In soccer they have many thousands of fans screaming, but it doesn't put them off what they are doing... although when you see how wide some shots are you do wonder! Years later he managed a sports centre near me. He organised a golf competition once and I was amazed at how a little movement miles away from him put him off his putt on the green.
2) Snooker players have to have complete silence when taking a shot, otherwise they lose concentration. I used to watch the Mosconi Cup, the 9-ball pool version of the Ryder cup between USA and Europe. Anyway, in the early days the European team had a few snooker players. Spectators were usually quite vocal during games, but somehow it didn't put those snooker players off!! So, why the difference???
I still think professionals should learn to concentrate on what they are doing and block out what is gong on around them; if I can do it I'm sure they should be able to too.