Rep. Ken Buck (R-CO) sharply criticized his fellow House Republicans for latching onto the testimony of an “FBI informant” who was arrested last week and accused of peddling lies straight from Kremlin disinformation operators. “We were warned at the time that we received the document outlining this witness’s testimony, we were warned that the credibility of this statement was not known,” Buck told CNN’s Kaitlan Collins, reported Edith Olmsted for The Daily Beast. “And yet, people, my colleagues went out and talked to the public about how this was credible and how it was damning and how it prov…