The Senate sergeant at arms and relevant congressional staff have been notified about changes to the chamber's informal dress code, which will go into effect on Monday.
Although senators will benefit from the change by being permitted to sport casual clothes in the Senate chamber, their staffs are still required to wear business clothes under the old dress code. People other than senators who walk on to the Senate floor will also need to wear business attire, which for men means a jacket and a tie.
Hence this part, perhaps?
Rules for thee, not for me.