I would argue that the reason these results aren’t reported by the MSM is because Rasmussen is not considered an impartial and trusted source. From Wikipedia:
“After the 2010 midterm elections, Silver concluded that Rasmussen’s polls were the least accurate of the major pollsters in 2010, having an average error of 5.8 points and a pro-Republican bias of 3.9 points according to Silver’s model.”
“Time magazine has described Rasmussen Reports as a “conservative-leaning polling group.” The Washington Post called Rasmussen a “polarizing pollster.” John Zogby said that Scott Rasmussen has a “conservative constituency.” The Center for Public Integrity listed “Scott Rasmussen Inc” as a paid consultant for the 2004 George W. Bush campaign. The Washington Post reported that the 2004 Bush re-election campaign had used a feature on the Rasmussen Reports website that allowed customers to program their own polls, and that Rasmussen asserted that he had not written any of the questions nor assisted Republicans.
Rasmussen has received criticism over the wording in its polls. Asking a polling question with different wording can affect the results of the poll; the commentators in question allege that the questions Rasmussen ask in polls are skewed in order to favor a specific response. For instance, when Rasmussen polled whether Republican voters thought Rush Limbaugh was the leader of their party, the specific question they asked was: “Agree or Disagree: ‘Rush Limbaugh is the leader of the Republican Party — he says jump and they say how high.’”
Talking Points Memo has questioned the methodology of Rasmussen’s Presidential Approval Index, which takes into account only those who “strongly” approve or disapprove of the President’s job performance. TPM noted that this inherently skews negative, and reported that multiple polling experts were critical of the concept. A New York Times article claims Ramussen Reports research has a “record of relying on dubious sampling and weighting techniques.”