Stop blaming the victim.
Girls have the right to reject the romantic / sexual advances of boys. And they do not deserve to be murdered for it. And such rejection is not a valid justification for going on a killing spree.
I attended a routine council meeting in our area and someone asked, Does the high school have metal detectors and the answer was No. The response of someone connected with the school board said basically that it would paralyze the daily operations of the school to have crowds of students backed up in lines going through a check point, the detectors don’t catch everything (some guns are now plastic), and the threat of a live shooting is still rare compared to the number of schools in operation.