It would be interesting to see this challenged for the case where interstate commerce isn't involved. I know the federal government has regularly asserted jurisdiction under the premise that drugs that don't cross state lines still affect interstate prices. I doubt it would be successfully challenged, but it would still be interesting to see it challenged. (I'm not a lawyer. This is not legal advice.)

All commerce is interstate commerce since the constitution got shredded by the courts.

What would be the challenge to affirm, the right to take a tax deduction on purely intrastate commerce? The feds might like that case because it furtheraffirms their ability to tax anyway they seem fit on purely intrastate commerce too.

I think it relies on you taking the deductions to begin with and the IRS saying “heyyy waaait a minute, some of these deductions in the trafficking of scheduled substances violate Section 230E, the others good though!” Which .. isnt really that farfetched but aside from the tax court case you could be facing a defrauding the US government criminal charge, and other stuff actual lawyers might be more aware of.