There is. It’s substantial, but much more subtle than on Reddit. Slurs and outright sexism usually get you banned pretty quick here, so it’s largely just the casual sexism left, but it runs pretty deep. And it’s been here at least as long as I have overall (my oldest account is about 3 yo). In the original wave, the shitty population drove off the vast majority of cis female users within 6 months, which is a huge part of why the demographics around here are so heavily skewed toward men. This is also why the women’s communities, which all died out and were resurrected during the second Lemmy population boom, are so heavily policed to shut men down.
You can tell we have such a population because all posts like these about women getting anything at all, good or bad, always, without fail, have an absolute glut of comments. If you then take the time to read all of them, a solid percentage are very clearly motivated by sexism. Now, commenters are obviously self-selecting, so it’s impossible to say in absolute terms, but of the people who choose to comment on such things, and generously leaving out any comments that may just be poorly worded, I’ve typically seen between 10 and 30% of the comments have such motivations, depending how old the post is and how much visibility it got. It’s not always the same people, either, it’s different shitty people most of the time. Downvotes also flow like wine if you challenge those comments, or call out the trend.
If you, as a passenger, notice no difference in service, because they still find someone to cover the ride in the big pool of potential drivers who aren’t women who only drive for women, does it actually matter if some of the drivers are personally refusing to serve you? Have you actually been discriminated against by the service? Would you even know it happened? I doubt it.