They can't focus on what was wrong about him because it will undermine their entire philosophy going all the way back to The Community Mental Health Act of 1963 (CMHA). Instead, they let the mentally ill roam at will within the general population with no regard to the myriad problems that result.
When I have time I must look up a recent article that said either Obama's Dept of Just Us or NY State decided to discontinue a certain class of group homes for mentally ill patients because those homes required that the patients stay on their meds. WTF???
Gun control is entirely ineffective in preventing another such incident; the steps being taken in New York are almost certain to ENSURE another such incident. With the re-election of Obama we have truly put the lunatics in charge of the asylum called the United States of America.