Maybe they were all friends of Paul Casey!!!
As an Englishman living here in the US I can maybe help out a little...
As a race in general we are a reserved bunch, who take a while to warm to strangers, especially whilst in a holy place like the golf course, or for that matter, a soccer filed or a soccer stadium.
We are wary of strange speaking folks because we usually end up going to war with them because we think it is the polite thing to do{just kidding..no political agenda behind that comment}.
Joking aside, I think you were unlucky, I think we Brits like you Americans consider golf a great equaliser, if you are on the golf course you must be an okay guy....sure as a rule we are a little more reserved and a bit slower to slap you on the back and divulge family secrets, but then most people are compared to Americans.
Lets face it you guys are just very friendly as a whole and enjoy conversation more than most other nationals,but once we warm up...we are all just golfers
GCA is just the best, where else can you have this kind of discussion about the greatest game in the world!!!!