It’s not a conspiracy or even hidden. The media shows what they want to show. They showed this shooting until they achieved their goals and stopped showing it. It is absolutely possible that each major media corporation did exactly what they wanted for their own goals at the time, no coordination needed, just that most of them are politically similar so their goals were fairly close. Shootings where attention promotes left leaning ideology are kept in the spotlight so long as they generate attention, any time that a right leaning narrative pops up they instantly drop all coverage. This isn’t a crazy conspiracy, it is a simple fact. Vegas resulted in Trump banning bump stocks; it succeeded and then was forgotten for whatever the next useful headline was that popped up.