I saw them too. Are you by chance colorblind? I have read that colorblind people learn to spot hidden objects by their outline and not by the difference in color.
I didn't know I was color blind until I got married. Then my wife started asking me "You're not wearing that, are you?" To which I'd reply "No, ah, I was just seeing if these still fit..." ;-)
When I'm playing "find what doesn't belong" I do a quick scan for discordant coloring or patterns. Then I do a slower scan looking for un-natural shapes - straight lines, even curves. I actually spotted these guys from right to left. The guy on the far right was easiest. Full disclosure though, I thought there was one more in the middle that turned out to be just a shadow.