Former President Barack Obama lashed into “woke culture” at his Obama Foundation Summit in Chicago Tuesday.

“This idea of purity and you’re never compromised and you’re politically woke, and all that stuff — you should get over that quickly,” said Obama.

“The world is messy. There are ambiguities. People who do really good stuff have flaws.”

The ex-president also highlighted the discipline required for change and the ills of using social media to demean and criticize without doing anything about issues. “It’s this constant of fine-tuning, of matching your values, your actions, and your impact. And that takes time,” Obama said.

“I do get a sense sometimes now among certain young people, and this is accelerated by social media, that the way of me making change is to be as judgmental as possible about other people and that’s enough,” he said.

“Like if I tweet or hashtag about how you didn’t do something right, or used the wrong verb, then I can sit back and feel pretty good about myself because: ‘Man, did you see how woke I was? I called you out.'”

“That is not activism,” he concluded. “That is not bringing about change. If all you’re doing is casting stones, you are probably not going to get that far.”

Other speakers at the summit include former first lady Michelle Obama, award-winning filmmaker Ava DuVernay and Emmy-winning actor Billy Porter.