Malkin is clearly on the defensive for having opposed the Homeland Security report warning of a rising danger of right wing domestic terrorism. The world has seen with their own eyes recent right wing terrorist attacks in Pittsburgh, Wichita and Washington, D.C.. Now she's left with nothing to say but "who are you going to believe, me or your own eyes".
Her blog post called The DHS “right-wing extremism” report and the Holocaust shooter is a clumsy attempt at slight of hand which focuses on the report's warning about veterans going terrorist a la Timothy McVeigh and excludes other aspects of the report. Obviously, this warning about vets didn't apply to aged vets of the Second World War. Malkin mocks those who feel the report has been proven correct by highlighting the age of the Holocaust Museum shooter. Of course, this is dishonest because the report dealt with the threat of domestic right wing terrorism in general, not only with veterans.
Like the arguments of Rush Limbaugh and Fox News, Malkin's argument by deceptively presenting only a portion of the facts serves mostly to misinform those who are on her side. In this instance, this form of argument may make her and her supporters feel better about their strident opposition to a report warning of exactly the sort of domestic terror we've been witnessing recently, but it does nothing to address the real issue. Ultimately, her arguments' extreme disassociation from obvious facts will serve to marginalize her. Insofar as the Republicans follow these opinion-makers, they also will be marginalized.
Furthermore, contrary to what Malkin offensively and baselessly asserts, no one on the left is "gleeful" about the attack on the Holocaust Museum confirming the conclusions of the DHS report. Mostly, the reaction on the left has been outrage and sadness. Falsely claiming that your opponents delight in a tragedy of this dimension is a low form of argument, closer to slander than to journalism or political opinion.