Aircraft, motor vehicles, electronics, most medical equipment and procedures, etc., aren't either. So who has the authority to regulate and where did they get it?
The states have the only Constitutional authority over these intrastate matters. The feds seized unConstitutional power over them with the FDR Court's Wickard v Filburn "substantial effect" perversion of the Interstate Commerce Clause, which empowered liberal big government.
Who decides what is to be regulated, controlled, restricted, licensed or banned?
Under our Constitution, the states.
So you are comfortable with the states having the authority to ban firearms?