Republicans attack harder when you show weakness
War Room: "But even Democrats who joined Republicans in condemning the MoveOn ad are finding themselves subject to the continuing attack. Consider the plight of Illinois Democratic Rep. Melissa Bean. When the MoveOn ad first appeared, the National Republican Congressional Committee put out a press release in which it asked whether Bean would 'denounce the group's despicable behavior,' then sneered, 'Don't count on it.' Bean proceeded to vote with Republicans in condemning the MoveOn ad. The thanks she gets? One of Bean's prospective Republican opponents in 2008 puts out a press release accusing her of 'blatant hypocrisy' for voting to condemn the MoveOn ad even as she 'accepts huge sums of money from liberal groups like MoveOn.org, which advocates surrendering to al-Qaida and other Islamic terrorist organizations in Iraq, and launches vicious personal attacks against well-respected four star generals.' As the Swamp notes, Bean hasn't received any MoveOn money since 2004."
This is a point that should be obvious to any Democratic politician but which many of them repeatedly fail to understand: going along with an outbreak of Republican Outrage Syndrome will not protect you from being the subject of said outrage.
Undoubtedly there were some (foolish) Democrats who agreed with the outrage about the BetrayUs ad and thus cast an honest (but still foolish) vote in favor of the measure (Sen. Webb being a good example). But there were also, undoubtedly, many Democrats who vote for it out of a naive (as well as foolish) belief that it would somehow protect them from subsequent attack. The story above demonstrates just how naive that belief was.
If there is one guarantee about Republican political strategy it is that the minute you retreat in any battle is the moment they will double-up the attacks against you. They may hate it when groups like MoveOn exhibit any kind of gumption by questioning the credibility of their chosen spokesperson. But they hate it even more when their opponents demonstrate weakness. It just compounds their hate with disgust.