How many absolutist 2nd amendment supporters would support a law that would allow this kids firearms to be confiscated because he said some abhorrent things on a youtube video??
Said some abhorrent things on you tube? Obviously you didn't bother to read the article I linked to. So I'll summarize it for you.
When he was in the fourth grade he liked to bloody up squirrels with his pellet gun, and then he started on chickens. As a teenager he snuck into his neighbor's yard and tried to get his dogs to attack their baby pigs. One neighbor saw him ramming long sticks into rabbit holes, apparently trying to kill anything trapped inside. Some neighbors said they called the cops on him frequently, and cop cars were at his house regularly to deal with the latest complaint against him.
Later he became more isolated, withdrawing from even his brother. Then others finally withdrew from him because he started posting scary posts on Instagram and photos of stuff like the bloodied body of a dead frog, and that he wanted to become a school-shooter. Then he was expelled from school, lost his mother to pneumonia and became depressed. He had an explosive temper and seemed to get off on antagonizing others. A kid who grew up on the same block said that people were afraid of him and that just about everybody on his part of the street had a run-in with him; he picked fights with other kids, stole people's mail, threw rocks and vandalized property, got called stealing a neighbor's bike, got caught peeking into a woman's bedroom, and started throwing eggs at his neighbor's car.
Then the daughter of a neighbor drove past him as he was waiting for the school bus. Cruz attacked her car, slamming it with his backpack. She called the police, and they stationed an officer at the intersection to make sure he didn't throw anything at cars. At school he started selling knives out of his lunchbox, and posting on Instagram about guns and killing animals.
He was repeatedly suspended from school. The school administration sent out emails to teachers asking them to keep an eye on him. The Broward County Mayor told CNN that Cruz had been receiving treatment at a mental-health clinic for a while, but that he had not been to the clinic for more than a year. Furthermore, the FBI was tipped off about his violent behavior and threatening remarks. At least they admitted that they failed to follow protocol concerning investigating this guy.