That's a bit of an exaggeration. From the description of the bill on Rep. Carter's website, it's meant to encourage the purchase of gun safes and other locking devices; it doesn't make possessing or using them mandatory.
That said, you're right that the up-to-$1200 tax deduction is yet another subsidy for the relatively well-to-do.
And as critics of the bill point out, it's a pretty small step from encouraging something to requiring it.
Formerly known as Vanya.