So like... Is there anything a consumer can do to push back on this? Are there any alternative payment processors I can try to use or ask other businesses to use?

Like... This is supposed to be the one thing capitalism and the "free market" does successfully: connect supply with demand. We typically need government intervention to stop that and make sure supply is being created safely, and that demand for things that harm society is not met. However, here we have an entirely undemocratic process where one extremist minority group literally on the other side of the planet from me is somehow managing to influence the global oligopoly to throw their weight around and prevent me from buying what my allegedly democratic government has no issue with.