I think its something to do with the internet access provider that you are using which designates a country. You can get rid of the flag in your profile settings.
Not so fast... Are all your favourite restaurants "all you can eat buffets"? Do you own an assault rifle just in case? Would a great movie to you ideally feature one or more childrens cartoon "hero(s)"? LOL
I just connected to one in Oz via my VPN, and I had an Ozzy flag - so the OP is correct Back in UK now though - that was a quick round world trip