SCOTUS for instance, who might hear the case, are nominated by government executives, not the people. They have zero incentive to do anything other than to garner favors from the government. That is why you walk away with insane judgements like Wickard v Filburn.
Of course, you could argue the seizure is an 8th amendment violation. Then you would take note you can go to jail for 10 years for not paying a $5 tax for any other weapon as defined by the NFA, and starting next year you can go to jail for a decade for not paying a $0 tax.
For example: https://abcnews.go.com/Politics/supreme-court-allows-trump-c...
If your rights get in the way they'll just make it an administrative or civil fine like a traffic ticket or zoning violation.
Also, the case and possibly the entire law should be thrown out (depending on what it says) because the crime wasn’t actually committed.