Taxing a repugnant transaction, medical marijuana version

Steve Levitt's post When Taxpayers Welcome Taxes, is about a medical marijuana provider who lobbied to have his business taxed. Levitt speculates why:
"The real answer, I suspect, is that he is generating $19 million a year in revenues selling in a market (medical marijuana) that is barely legal. And DeAngelo probably suspects that taxation will increase the likelihood that his business remains legal, for two reasons. "

I'm inclined to agree. This reminds me of the similar case of legal brothels in Nevada.