Tax Code section 280E denies tax deductions for advertising marijuana. That rule tends to promote public health, and to keep the noise down on branding and promotion. Similar rules for alcohol, tobacco, and direct-to-consumer pharmaceutical ads have been suggested, too.
Denying tax deductions for advertising expenses is not a new and fresh idea. Google “25 Years of Initiatives to Tax Advertising” for a link to the document from the Association of National Advertisers. Even standard advertising of non-temptation goods tends to have a useful life of over a year (I still remember cola jingles from my youth). So amortization of all advertising expenses might make sense.