Why Are Republicans jumping all over Anthony Weiner to Resign? David Vitter is still Senator He cheated?

There was no ethics investigation.. Eric Cantor was on Fox news saying that " Democrats should give their money back to Weiner, Weiner should Resign". In the past 4 years there have been 2 Republican congressman, one of whom was doing hookers in DC, neither of them resigned or was asked to resign.. No ethics investigations were launched.. No Democrats demanded them to resign. David Vitter... Is still in the Senate, He cheated on his wife 2 years ago. He was not demanded to resign by Democrats. Republicans did not demand his resign. RNC Campaign funds were used at a Bondage strip club in LA last year, Thousands of dollars were spent at this Lesbian Bondage club, Democrats did not launch an investigation, Republicans did not ask Michael Steele Resign. But Anthony Weiner, sends some R rated photo's and has some sleazy conversations, and he should resign? Over that? He didn't actually Pay any hookers like the Republican Congressman, Who did not resign. He didn't actually cheat on his wife, like David Vitter, Who is still A Senator. Why are Republicans harping on Anthony Weiner?