As a consequentialist pro-feminist, I'm bound to attack anything that I think will significantly support patriarchy.

I'm not sure attacking everything that contributes to patriarchy is more important than attacking only the things intrinsic to patriarchy, eg gender bias. Otherwise, you're obligated to attack patriarchy about 10000 times a day, and it makes your advocacy seem weaker. Also, you should really be considering whether or not the minor reduction in patriarchy is worth the slightly larger, but still small, move away from evolutionary psychology.

I think a large part of my disagreement here is that I don't think evolutionary psychology really results in an all that much more strengthened form of patriarchy. I can believe that it probably has a very tiny effect, but it doesn't seem very significant to me. Part of this is because I think patriarchy would be really strong even without any media help, and part of this is because I don't think the media really does what you think it does with respect to evolutionary psychology. The other large part of my disagreement is that I'm not sure if that reduction of patriarchy is worth stopping evolutionary psychology, which seems very useful.

It seems to me that stopping gender bias is both necessary and sufficient to stop patriarchy or any of patriarchy's important effects. I don't think that attacking anything "patriarchal" besides gender bias is worth it if there's a different advantage to keeping that thing around. I'd rather just focus on attacking gender bias alone, and then get the rewards of all the other things.

Further, what's the difference between saying "sexism is a property of evolutionary psychology" and "evolutionary psychology has sexist effects?" In my language, that would be "evolutionary psychology perpetuates patriarchy" and that, to me, is the referent of the word "sexist." What would you taboo "sexism" with if not that?

I define sexism as unwarranted prejudice or discrimination based on sex. That's how most people define it too, I think. Under your definition of sexism, it gets confusing, because we can't tell if you're intrinsically opposed to something based on the necessary qualities of that thing, or if you're pointing out that the thing will ultimately end up perpetuating patriarchy.

Also, the broader a definition gets, the less useful it becomes. Your definition is so vague as to apply to pretty much everything (because everything that helps society, such as crops, rain, technology, interpersonal interactions, etc. ends up supporting the current system, which is currently patriarchal). Your definition also applies to certain things in some scenarios but not in others, your definition is more about overall processes than specific qualities, which makes it more complex and makes it inappropriate to use as a simple label, like you did.

Unfair gender situations deserve special attention, which means that we need a word that specifically applies to only them, and which can very clearly be proven to apply or to not apply. Fortunately, we already have that word.