He said that in reference to coworkers at your job. Some of the women are “mean girls” who gossip about other people, some guys are bullies (obviously not in an in-your-face way), and some of the adults just act like high school students. The only difference is that some of your coworkers are in their 20s, 30s, or 40s.
Would you say thats accurate?
There are also marked biological changes that affect behaviour though, like the development of the prefrontal cortex, but I agree: it’s a matter of personal responsibility and not everyone gets there, sadly.