That's a reasonable take, for sure, and it makes a lot of sense.

However, it is a bit of a rationalization to explain to yourself why you support her. It is analogous to not voting because you don't think you'll sway the election, that your vote doesn't matter, in the sense that if enough people do it it does begin to have an impact.

Also, it isn't about not giving her a lavish lifestyle, it is more about sending a message that her brand of hate isn't welcome or tolerated. While she will make millions off of investments, if she sees that her bottom line was hurt because of her words she may, ideally, re-think them. Perhaps reflect on them, in a perfect world.

Admittedly, in reality she probably will only dig in deeper and feel victimized. But at least I'll sleep better at night

For me it's more of a rubber meets road issue. Whenever a Harry Potter franchise something is released it becomes a circus of highly performative transphobia that spills into trans spaces as certain people want to not just enjoy their Potter related paraphernalia.. they suddenly find a wave of harassment to ride and do not seem content until they have hunted down trans spaces, people or allies to rub our noses in the fact they are having a really good time while spewing anti-trans sentiments everywhere as they do.

Being a trans person in public and seeing someone wearing Harry Potter related merch out and proud in the world can be a red flag in the sense that marks out a person as more than likely mildly anti trans on the safer side but a decent number of them who have held strong til this point are not nessisarily shy about being openly hostile in a very general - non fandom related sense. If I walk into a place with a bunch of people wearing wizarding house t-shirts and pins... I find away to excuse myself and leave.

The money isn't even much a factor anymore. The inner fandom has become so toxic it basically just provides the mechanical structure of an organized hate group while nominally being about the franchise.