So she should fuck off then and quit trying to interfere with anyone actually cockblocking the sociopaths who crossed the line of fucking with him on criminal levels.
The most charitable interpretation would be that she has an instinctual reaction to kiwi farms. On the whole it fucks with Chris so it isn't to be trusted. Chris would be better off disengaging from all internet socialization since he is not capable of filtering the trolls from the helpful ones. Up until recent history, that wouldn't have been a bad policy. In the past, I have been more sympathetic towards Anna. I always interpreted it as she didn't really want to put much time in effort into it, but thought that the occasional asspat and internet=bad reminder would help.
This time is different though. There are two facts that seem like they should be self evident to anyone. First, there are enough alarm bells out there that people should see something needs to be done. Second, Anna is in a somewhat unique position to act. She has credibility with Chris. She probably has some credibility with Barb. And, for the reasons I talked about earlier, she presumably has a lot more credibility with the authorities.
So I think that does create an obligation. If you are walking home alone late at night alone, and you see a three year old kid wandering around, you have an obligation to act. It wasn't a responsibility you asked for, but something needs to be done, and you are the one in the best position to do it.
What she has done seems to be the worst of all possible choices. Ideally, she would have worked with those trying to help Chris. Slightly less ideally, but perhaps reasonably, she would have said "thanks for letting me know. I don't really trust you, but I am going to do whatever I can do to solve this problem with the help of Rocky, etc."
Even worse would have been to walk away from the problem. But what she is doing is the most destructive, she is actively making things worse.