Would background checks have prevented this? I haven't seen any evidence to suggest that, but I suppose it's possible. In which case this could happen anywhere. And it does... Even in cities and states with very strict gun laws.
Quite possibly yes. It could have stopped this guy from getting a gun and many like him. Background checks can save lives.
The supposed gun control debate is and has always been a moot point. America was created specifically as a country that guarantees the total freedom to say anything you want anywhere, carry any weapon you want anywhere, travel freely anywhere, refuse any "medical" or investigative procedures you want to refuse... Read The Bill of Rights. Government cannot enact/enforce anything at all that weakens these inalienable rights for any reason at any time. Period. To do so is treason, which automatically eliminates any claim to government office, rank or position of authority. Constitutional facts matter.
Yes. In that hypothetical, there's no harm, no foul. Even in far left Oregon it's not a crime to say you are going to harm someone, otherwise there'd be no Democrats walking free.
Toddlers can kick some ass. Just read an article recently about a preschool kid who sent a teacher to the hospital.
It's a crime to walk into a school with a gun in Oregon and say you are going to shoot someone. The police would be called and you would be escorted to jail, do not pass go, or at least to a mental institution. There is harm and there is foul in it.
That's the only thing about being a hero in that situation. You disarm the gunman and hold onto the gun because you don't want him to get back ahold of it. Then the police arrive and mistake you for the gunman and shoot you. That makes it tough to want to act in those situations. But, I guess you stopped him from shooting people and now get to sue the city and get rich.