Essentially what Mr. Litzelman described is a problem that isn't even one that can be solved with police.
However, Mr. Litzelman described one bad action by one SRO to dismiss the rest. It Mr. Litzelman would have read the findings of the commission created to investigate the shooting in Parkland, maybe his opinions might be more constructive.
However, Mr. Litzelman should take an honest look at school shootings. Perhaps he could do more than simply parrot the numbers provided by the Center for Homeland Defense and Security.
In the 2019 calendar year, there were 12 student deaths attributable to gunshot wounds. The leading cause was suicide.
Statistically speaking, the safest place for a student to be is a K-12 public school. They are at a higher risk of injury or death virtually anywhere else, including in their own homes.
I think Mr. Litzelman needs to do a bit more independent research.