Why? I mean, if you are just looking at nudity - even if the men are 'prepared for sex' - at the end of the day, it is just nudity. I've worked in nursing homes. Other folks work at hospitals. Lots of folks see nudity everyday. Lots of those folks see genitals daily, in a much more intimate way than a dick pic.
I don't really get what is so unhealthy about it. There is nothing inherently wrong with simple nudity in general, even when it is suggestive.