Could it be because Jim Matheson wasn't forced into a primary campaign, and won't be campaigning until before the November election? Could it also be that replacing a relatively conservative Democrat with another Democrat, would achieve nothing?
IOW, the tancredo/bay buchanan PAC couldn't spend their monetary resources on a person(Jim Matheson) who would vote for nancy pelosi as Speaker of the House, their(tancredo/bay buchanan) political monetary resources were better spent on trying to unseat a 100% ACU conservative.
JMO sounds kinda of agent provacateurish, IMO.