It's only wrong when you do it

It is not in the best interest of the party to challenge incumbent legislators whose views do not mesh with your own. It only serves to divide the party and jeopardize control of the House and future control of the Senate. That mime has been consistently repeated by mainstream Republicans since 2010 when several Republican careers were laid to waste in an upheaval the resulted in control of the House and a net gain of 7 senators.
Evidently the strategy has changed or is only meant to apply to the Tea Party. Two very establishment Republicans will attend a fund raiser in what is probably a futile attempt to oust a Tea Party favorite, libertarian leaning, Michigan Congressman Justin Amash. Congressmen Devin Nunes of California and Mike Rogers of Michigan will attend a $1,000 per plate breakfast event for congressional candidate Brian Ellis who is currently trailing Amash by 19 points in the polls.
Both Rogers and Nunes have chipped in $5,000 to rid country of what they consider the anarchist from Grand Rapids. In the spirit of comity and party unity Nunes describes Amash as " Al Qaeda’s best friend in the Congress".
Amash, as one of the NSA's harshest congressional critics, has upset Rogers but his chief fault may be he is not beholden to big business and Wall Street.

“The extreme radicals are going to get reelected because they come from districts where they don’t need to raise that much money,” said Greg Valliere, chief political strategist of the Potomac Research Group. “This new tea party movement is not particularly pro-business. They certainly are not pro-Wall Street and pro-big banks. That is a new strain in the Republican party that worries many on Wall Street.”

Oh you prefer congressmen from districts where they must raise a lot of money to hold office? But what about the "corrosive effect" of big money on democracy when the money comes from the Koch brothers?
God forbid Lloyd Blankfein or Jamie Dimon lose a night sleep over a congressman all the way out in Michigan. Perhaps the message Rogers and Nunes want to send to the Tea Party is, "It's only wrong when you do it".