Whereas not many years ago, college students wore coat and tie to football games, you now can't guarantee that half the adults there won't show up in shorts. You can't do gravitas in an earth-toned sport shirt. It looks silly. Yes, they do. Not only do they want it, they expect it.
Government is serious business.
You want it done by serious people. Serious people go to the trouble of looking serious, so that others may see them this way. Even Bill Clinton understands that without a necktie you're not totally serious. As for Clinton's idol, John F. Kennedy, he understood the law thoroughly. You might hate the new frontier, but, partly by how they dressed, you knew the new frontiersmen took themselves seriously.