I've been reading The Destiny Report, and I have yet to come across a single person therin (including the author) who seems like they're remotely a reasonable, mature person. (With the possible exception of a minor character named "Drew".)

The impression I get is that Destiny and the community of streamers they're a part of are effectively performing a massive nonstop soap opera of their lives. Every part of their personal life is made public for the enjoyment of strangers online. The more drama their personal lives include, the more popular their streams get. The more popular their streams get, the more drama this publicity causes in their personal lives. The incentives here are terrible.

This vicious cycle means that people with poor impulse control tend to become more popular, and people who are popular must behave in that way if they want to remain popular. In some cases they may be seriously mentally ill, and rather than try to help them (which would almost certainly involve taking the spotlight off of their personal lives), the watchers just egg on self-destructive behavior.

One day a streamer is viciously attacking another, attempting to destroy their lives by getting them fired, harassed off the internet, or in one case actually planning a murder. The next day they're posting an emotional makeup video about how it was all just a big misunderstanding and really they're best friends. Then next week they're back to hating each other. (See the Destiny community's obsession with "bridges" and how often they're "broken" and "rebuilt".)

They've let online disinhibition bias completely dominate their lives, and brought the same lack of moderation and control that plagues the internet into their real lives as well.

This whole time everybody is having sex with everybody else, none of them discuss or respect boundaries or the emotional needs of any of the participants in these relationships, and all of them regularly levy accusations of sexual harassment, sexual exploitation, etc. against each other as fuel for the internet outrage engine. (These accusations are often false and often true, and determining which is which doesn't seem to be a concern.)

The fact that this lifestyle is being broadcast to millions of impressionable young people online who often have no other healthy relationships to keep them grounded seems bad. Tens of thousands of teenagers are growing up with this parasocial relationship, looking up to these people; wanting to start their own streams, eagerly accepting any invitation from a famous streamer, and internalizing that this form of extreme antisocial and self-destructive behavior is normal.

The only positive effect I've seen Destiny praised for is converting people away from internet radicalization, but when the method of conversion is "win the insult fight", this is a symmetric weapon. Destiny does at times use intelligent arguments, and Destiny seems a step above other streamers in terms of truthseeking behavior (I enjoyed his debate with Eliezer at Manifest), but I expect the net effect on epistemic norms has still been negative, and that's on top of all the damage they've done to people's idea of what a healthy polyamerous relationship should look like.