I had never heard the word "romper" in my life, until this week. Suddenly, I am seeing this everywhere on Facebook. As I gather, it's some kind of viral trend.
I saw a video of the guys from the OP's picture, and it was about trying to normalize non-masculine clothing in men's fashion. I'm all for men dressing in more feminine attire, if they can do it tastefully, (Ezra Furman looks great in lady's clothing, for example.) but this just looks terrible. It isn't even feminine. It just looks like something that a young child would wear.