Actually, they only view primary challenges as purges when they come from the left. I didn't hear any of the aristocrats complain about Ed Case's challenge to Sen. Akaka, nor when Henry Cuellar beat Ciro Rodriguez in 2004.
So not "especially when they come from the left" but "only when they come from the left."
And neither did you hear about the guy, a Republican moderate, who was primaried by the CfG candidate in Michigan in the House.
