From what I've seen it's more common for men to be into fetishes in general. When reading papers in scientific journals I see a lot more male participants.
I believe it's some combination of the factors that:
1. Some men are more encouraged to embrace sexuality [varies greatly by region]. This may lead to an easier time labelling a fetish as a fetish for men, or for women may repress "non-standard" desires.
2. The fact that a responsive desire style is more common in women
3. That hookups/sexting can be less desirable/fulfilling for women
4. Negative experiences with attention that's received when disclosing you're a woman online.
So one or more of the above coupled with the common assumption is that someone is male online when not stated otherwise, it makes the gender gap look even more vast. Of course, nobody of any gender is going to fit a generic mold, and since experiences differ quite a lot these aren't accurate to every person. This is just based on experiences, observations, and what I've read in studies and online.
FWIW, I find places like bluesky/twitter/tumblr have a lot more women there that are into diapers.