Rowling is a bigot and it's unethical to promote her works, even indirectly.
She uses her wealth and fame, legitimized by continued engagement and spending with the Harry Potter IP, to attack, demonize, and spread hatred about entire groups of LGBT+ people.
This isn't a branded product, and I know no money directly ends up in a bigot's pocket because of this, but every time her works are referenced it endorses her hatred.