Ouch! The usually-acerbic Morgan Stewart, co-host of E!'s Nightly Pop, did the unthinkable the other night -- she criticized Justin Bieber!!!

The Rich Kids of Beverly Hills alum critiqued Bieber's comeback performance at Coachella, accusing him of lip syncing and of having acne! Horrors!

As the show's panel discussed the previous weekend's music festival, Stewart started by saying "... the poor music started without him," when talking about Justin's performance of his hit single "Sorry." Sorry, NOT sorry! Morgan went on to critique: "I did not realize it was gonna be that bad ... He definitely looks like he put an OXY pad on that forehead, but I don’t care. That is f–ked up!"

Well Justin's not taking the negativity -- and rather than defend any of her direct criticisms, he took to Twitter in defense of being positive and not breaking people down. He wrote, "Imagine if you spent even half the time you spend laughing at other peoples expense actually building people up and encouraging people how much positivity you could bring. What hurts about this is the fact that you have a platform to make a difference and rather than being positive you belittle people."

He went on ... "Think about how awesome it felt for me to be on that stage after being away for so long the excitement and joy it gave me doing the thing i love the most. I sang to [a] backtrack like most cameos do this is a normal thing, and rather than try and make people feel accepted and loved you find things to pick apart like the world isn’t full of that already."

His stage partner Ariana Grande also took to social media to defend Biebs, writing, "People look so ugly when they talk about other people like this, it’s crazy. like no matter how pretty you are or how long u spent getting ready, u ugly to me now. HOW do people watch s—t like this lmao." She went on to explain, "We also decided to do this ten minutes before my set started. we had 0 soundcheck, 0 rehearsal,” Grande noted. “U were singing with the back tracking like most cameos do. people are bored. people don’t know how it feels to be under such scrutiny. the world was happy to have u on stage again." Hailey Baldwin re-Tweeted Grande's message.

He's right! But at the same time, so is she! She gets ratings based on being funny and we all like to have a good laugh. If every single thing out of a show host's mouth is congratulatory, wouldn't it be kinda boring? Is there room for "mean" humor? Or are we past that in this age of hyper-political correctness?