Short answer: no, women are not the only victims.
Longer answer that attempts not to spoil too much: while the main killer definitely leaves quite a few bodies in his wake, there are just as many named women characters (that is, they have names and interact with the leads) as named male characters that are killed. While there are certainly aspects of the show that could be considered problematic (there’s a subplot that involves a baddie-of-the-week profiteering off of rape, although that’s not shown on-screen), the main killer simply kills those who are hindrances to him, no matter their gender. But there are definitely many brutal murders on this show, which I can understand being an issue for someone. Not all the deaths are due to the main killer, but all seem evenly divided along gender lines nonetheless.