Fetlife is not a dating app. They have actively not implemented features such as filter by age/gender in order to avoid becoming a dating app. If you are looking to get involved in your local kink community, Fetlife is the answer [0]. For anything else, it is garbage. If you try using it to get laid, you will just be pissing a bunch of people off.
[0] At least for my local kink community. Other areas might vary.