As a guy, this line was pretty funny, and I could see myself saying it (on an all male team). I might not say it in front of female coworkers though, but if I worked closely with one I may say it within earshot without thinking about it. It certainly wasn't an attack on the poster.
Are we just not allowed to talk about genitalia? I guess as a baseline rule it's inappropriate, sure, but he's not being suggestive or soliciting. As described, it's obviously a joke. Not sure where the offense is here other than he said "dick" in the workplace within earshot of someone who doesn't want to hear that.
I'll finish by saying that the rest of it was certainly uncalled for, but this one instance doesn't really stand on it's own as offensive.