It isn't for "no real effect". Harry Potter is a merchandise empire and it's important to see how that empire is being utilized. Open fan support of Harry Potter is often used as a direct open signal of anti-trans support and Terf ideology. Here in Vancouver where we have a larger than average population of trans and non-binary folk and more open accommodation to the community a billboard was put up saying "I❤️ JK Rowling" downtown because it's a more nebulous dogwhistle that wouldn't immediately ping Canada's hate speech laws so that the whole "Freedom of Speech" ploy could be envoked.

Whenever a new HP franchise item comes out there's a wave of people who flood online and sometimes in person trans spaces who use the barest veneer of support of the franchise as a means to say some truely awful things about trans people. Some don't even bother mentioning the franchise they just participate in the storming because they have the opportunity. Those spaces are often filled with vulnerable people seeking support and solidarity and these rushes can leave isolated trans people without community for weeks.

Here in Van someone wearing HP merch in any queer space is throwing up a flag that says "I am potentially an unsafe person."

Article of the billboard.

http://www.cbc.ca/amp/1.5722244

You don't have to give up your books. All we ask is that people do not white knight the author or the publication and merchandising empire which keeps making her influence into an active memetic weapon.