Regular people insult each other on impulse all the time. Sure it's rude, but Taemin did make Naeun cry with that stipid prank. Let's not think how "omg they're famous they need to be great examples of nice people". They're human, including the WGM staff, and they all make mistakes based on human emotions. So from now on, dear Shawols, think twice before you go all anal attentive over one small detail that was barely noticeable until recently.