Further there is no threat to wife and kids. It simply says they will join you in hell. BIG DIFFERENCE.
The misleading header falsely makes it seem as if the writer is threating to run a "blackout" - killing the whole family together.
Practically anyone can allege you are 'unfit' to own weapons.
Let's say your kid (Tommy) tells his friend (Joey) at school 'my dad has a lot of guns'. Next weekend Dad boo's kids taking a knee at a basketball game. Joey's mom is a BLM fanatic and is offended. She calls cops and says Tommy's Dad is a right winger anti Black racist and she know he has a lot of guns.
Your ex wife tells cops you threatened her (you didn't).