Why are they called Congresswo(men), and not Representatives?

Hola a todos. Senators are never called Congresswomen/men even though the Senate is the upper body of the US Congress, so why are Representatives called Congressman/woman? It implies that the Senate is not part of the congress. It’s sloppy language and I hear it from the corporate media talking heads as well. I also read it from people who don’t know our system: They don’t know that Senators serve 6 year terms and Representatives serve 2 year terms. I’m sure someone will rush to defend it, but there seems to be a glaring disconnect and that some people don’t seem to understand that anyone in the congress is technically a congresswoman or congressman, not just Representatives from the House of Representatives. If one insists on the sloppy language of Congressman/woman, when might we read Congresswoman Feinstein (the Senator from California)? Chau.—el barrio rosa