Seriously who is surprised? One need only spend about 5 seconds considering the two scenarios
In which scenario is the recipient more likely to say “wow — thanks!”? I would estimate, based on personal experience, that if a woman is at least somewhat attractive and sends a naked picture of herself to a random male, at least 95% of the time it will be sincerely appreciated and no complaints will be made. I would estimate in the reversed genders, you’d get a 95% “oh yuck, I did not need to see that” response. Which gender, therefore, is going to experience positive feedback and be more likely to repeat?
Or do I live among a group of highly abnormal humans?