(Assuming we have sensible community norms like "mentally flip the genders in your post before you post to check this is normal objectifying rather than super-offensive objectifying", which I think we can do.)

Most feminists believe that the objectification of women is harmful not merely because it is objectification per se, but because is embedded in/contributes to a culture in which objectification is heavily asymmetric between genders, both in its frequency and in its impact. If this is right, then mentally flipping genders in a post isn't a reliable guide to whether the objectification in that post is a problem.