He only cares about fame and attention, he's a puppet for the Dems who've fed him all his lines, he relies on the incredibly cowardly tactic of hiding behind his youth and the fact that he's a Parkland student to try and deflect any kind of criticism or reasonable debate on the subject, he's openly insulted the good Senator Rubio and openly blamed him for the shooting (While never once mentioning the incredibly incompetent and cowardly law enforcement officials who knew Cruz was dangerous and planning a school shooting and yet did nothing, or the deputy who stood down in the middle of the shooting), and he's exploiting the deaths of his classmates to expand his own 15 minutes of fame (A fact several other Parkland students have openly called him out on, including one whose sister was killed in the shooting).
Are all of those reason enough?