This may be true sometimes, but I do not believe it is always the case. You need to be able to tell who is just a sh*t-stirrer and who has been emotionally harmed.
Sh*t-stirrers tend to be narcissistic, get a kick out of creating conflict, and have a real talent for keeping their own hands clean while they goad others into those conflicts. They tend to thrive in hierarchies of various sorts and are easy to recognize as an adult if you can remain detached and observe.
Psychiatric injury is a very different and very real thing, and people who have been repeatedly emotionally traumatized - for instance, by having to live with or work for sh*t-stirrers - may be both bitter and resentful about it, especially if they have not found any way to stop it, or have been trapped in an environment that is so inimical that their efforts are constantly and deliberately thwarted. As for instance when the sh*t-stirrer is their boss, or the CEO.
We have the term "abuse" or its equivalent in our languages for a reason.
A lot of magical thinking is peddled to people as a way of training them to disempower themselves and sabotage any social change that might benefit whoever their society (as small as a family or workplace, as large as a nation or "race") depends on victimizing. The notion that we create our own reality is first on that list, see also "the law of attraction", which is a tidy way to blame people for their misfortunes so that the blamer can feel superior and won't do anything to help them.
When abuse survivors are able to genuinely escape abuse - that is to say, they get away from a domestic abuser for example, then don't encounter another of the same, or workplace abuse, or church abuse, or any of the other variations - it can take years for them to heal, if they ever manage it. Part of that healing may require disclosure. Part of the injury may be a desperation to find someone, anyone, to whom they can disclose without being judged.
N.B. Lifeguards are trained to deal with the fact that a panicked, drowning swimmer will pull the lifeguard under if not appropriately restrained during rescue. This is not because the swimmer wants to drown and is trying to take the lifeguard with him or her. It is because we are not wired well for self preservation in that situation. The analogy holds.
Tread gently. If you don't know which it is, it's a lot more humane to assume injury than nefarious intent, and if their pain is too much for you to handle, the kindest thing to do is to just let them be in peace.
_________________
"I believe you find life such a problem because you think there are the good people and the bad people," said the man. "You're wrong, of course. There are, always and only, the bad people, but some of them are on opposite sides."
-- Terry Pratchett, Guards! Guards!