According to Callahan, why does a party of the Hamptons give us insight into social inequality and many Americans' anger at politicians?

When Lally Weymouth, senior associate editor for the Washington post, held a party in the Hamptons and he invited politicians and people that usually were on opposite sides regarding politics and they were all enoying the party together because of compromise, it lets us see that, while they make some of us think that they work hard for the good of the town and the people, they only want to benefit themselves, even if it means tolerating someone they don't like.