There is a scene in a French documentary in which a former Dassault boss displays his vintage wine collection as one of his many tools to ease arms supply deals with various nations. When the journalist asked him if it really works like this he responded, “Of course, because men are pigs!”

Not sure why you're surprised. That's just how business/networking/capitalism works everywhere on earth and it's been like that since the dawn of civilization. And why would Congress stop is since they're all getting the same benefits and don't even hide it?