Some thoughts in this area:
Male authors tend to have more "stickiness" - we continue to recommend Eddings and Feist and Jordan, but where are the female authors who were writing at that time and were, honestly, just as good as their male counterparts? (We're not all as assiduous as Nora in remembering the Sheri Teppers.)
- Tansy Rayner Roberts spoke very eloquently about this in her guest of honour speech at Melbourne's Continuum a couple of years ago.
Her speech is available online. In this speech she also noted the tendency for "recommendation lists" to include a token woman - usually Ursula le Guin (or Robin Hobb). Smurfette syndrome in real life.
There's an argument to be about whether fewer female writers write fantasy of the same quality, or whether male authors are more likely to be published at a lower quality. I remember reading some of Lindsay Buroker's work, and finding it at absolutely the same level (for me) as, say, Brent Weeks. (That is, imho, engagingly readable, pacey, but ultimately kinda meh.) Weeks is a bestselling trad-published author whose name gets bandied about a lot. Buroker is successful, but indie, and way fewer people know her name.
It's all very well to have personal disinterest in matters of author gender (or race, or sexuality, or...), but if all the market ever gives you is white males, your reading is necessarily going to be skewed towards white males.
I recall hearing that Mark Lawrence ran a poll on his blog asking whether people would have read his books if they were by Mary Lawrence instead. A significant number of people answered that they probably wouldn't have.
So it's not that people actively undermine female authors. It's (perhaps) just that they have to be twice as good to get half as much attention in the first place. People don't denigrate them for gender, they just leave them off recommendation lists. So there's no big stand to be taken, just that we need to keep asking "Where are the women? What are they writing? Who can you recommend?" because very often the default position is what we're fed, and what we're fed is 75% male (at least).
Some women writing really interesting high fantasy and arguably underrepresented on recommendation lists: Amanda Downum, Rachel Hartman, Lois McMaster Bujold, Kate Elliott, Patrician McKillop, Megan Whalen Turner, Juliet Marillier, Ellen Kushner, Jennifer Fallon... and these are just the ones who appear on my GR shelves.

We here at FF have a
whole pinned thread about female authors, so clearly we're aware of the issue already. But I think it's good for us to also remind ourselves now and then, because it can be easy to slip back into not thinking about it, and the problem waxes and wanes, but hasn't gone away.