Thats a complex question, but maybe its more a cultural thing. I only remember seeing one convention being picketed here in the US, and even then they werent XJW's or at least they didnt identify themselves as so. I think Americans here are for any religion, anything goes, as long as its a religion. Thats why people are reluctant to picket against any religion they see as dangerous. Organized religion runs the show here in America, while personal salvation in Jesus is downplayed. Thats why im still a little leery of organized religion. The religion card is played well in this country, and Jehovah's Witnesses have learned to master the art of manipulating the law.
Dave