“Any tax must have the purpose of raising revenue and not designed to prohibit an activity.”
Legislators need only assert such purpose, not prove it does.
NFA taxes in no way “raise revenue” to any meaningful degree, and were clearly designed to prohibit an activity (to wit, at time of enactment, a >400% tax stifling exercise of the activity, limiting it only to professional “operators” & investors & the most devoted hobbyists).
There were several instances here in Alabama where local jurisdictions decided to move against adult movies. They had previously voted to ban them and lost that in court. So, like this liberal, they said we can just levy a huge tax on them. They enacted a $50 rental fee for all XXX movies. They lost that one in court too. For the reasons I cited.