The Little Shaman is a spiritual coach & specialist in cluster B personality disorders, with a popular YouTube show and clients worldwide.
To preface this discussion, let's be clear that this is not about never being negative or the so-called "toxic positivity" mentality. Humans are complex, and sometimes authenticity is not positive. Sometimes how you feel is negative. Sometimes things happen that suck. Sometimes things happen that hurt. Sometimes things happen that are unfair. We shouldn't wallow in these things, of course, but expressing your genuine, authentic feelings is important and sometimes, they're not positive. That's OK.
However, it's important to remember that sometimes the people or situations that this expressed negativity attracts should be regarded with caution. Narcissists often use strong emotions as a way to get in with people very quickly. For example, we usually think of flying monkeys as being the people who attack others on behalf of the narcissist due to the narcissist's manipulations or lies. Many people don't realize that many narcissists will actually attempt to become your flying monkey in order to create the appearance of intimacy or to ingratiate themselves to you. This is what they want and appreciate, so many of them will attempt to engage in this same behavior in order to start or perpetuate a relationship. They may even attack another person, speak out about something on your behalf or take some other action, even though you did not ask them to do so. When someone does not understand healthy boundaries or they are in a very vulnerable state (as many are when they are having a negative experience), they may not see this behavior for what it is, which is an enormous boundary violation.
The pathologically narcissistic person does not understand true intimacy. They don't understand interpersonal bonding. Their attempts at bonding usually look like boundary violations, enmeshment, commiseration and mimicry. To this end, if you say you don't like something or someone, they may attempt to "bond" over that by joining in the negativity regarding that thing or that person. If you say you are hurt or sad, they may attempt to "bond" over that by comforting or commiserating with you. This creates the appearance of intimacy and through subtle but very important virtue signaling usually encourages the other person (who may be in an excited or upset emotional state) to share more and builds trust faster: If someone doesn't like what I don't like, or if they hurt the same way I do, they must be like me. At the very least, they are not like this person or thing I don't like because they don't like it either, so they must be OK.
By creating the appearance of sharing, they are creating the appearance of intimacy. This is very important in building trust in relationships and using strong, negative feelings like pain, grief, injustice or betrayal as an opening is one of the fastest ways to do that. In much the same way that many narcissists will violate boundaries to create the appearance of intimacy by sharing too much too quickly about their own lives, they will also often lean in to others who are vulnerable enough to do so as well.
The virtue signaling achieved here is also very important. By agreeing or commiserating with the negativity, the narcissist is saying, "I'm not like that. I also disagree with that thing or that person. Therefore, you should think that I'm good by comparison to that thing or that person." This is the reflection of themselves they are looking for from the other person and it is usually exactly what they get.
"Oh, you think guys who ask for inappropriate pictures of you are lame and gross? I think those guys are lame and gross, too!" The unspoken message being given here is, I am not like that. By comparison I am better/safer/etc.
"Oh, you think girls who just date guys for their money are awful? I think they are awful, too!" Once again, the unspoken message is, I am not like that. By comparison, I am better.
Of course, lots of people agree with these things and lots of people really aren't like that. But the narcissist is not being sincere. They may not even be being honest. They are simply using something a person feels strongly about to make themselves look better and to find a way in. It is usually not through something positive. It can be, but it seems that they are able to relate much better through negativity, and that is probably no surprise. There is no real way to come out better in comparison when the discussion is about something positive, and narcissists are chronically unhappy people anyway. Many people realize, upon looking back over the reality, that their relationship with the narcissist seemed to revolve almost solely around negative topics or situations. They also often notice that the narcissist's conversations or attempts to bond with other people were the same. It isn't always like that, but many times it is.
This doesn't just happen in situations where a narcissist is trying to create new relationships or perpetuate existing ones, either. It also happens in situations where the narcissist doesn't even know the other person or people and isn't even really interested in getting to know them. We may see it on social media for example, where a stranger's negativity has hit too close to home and the narcissist feels attacked or called out by it, so they feel the need to defend or distance themselves from the negative judgment or label without somehow admitting that they identify with what has been said. Some narcissists achieve this by arguing or contradicting the negativity, but others achieve this by joining in the negativity, thereby proving to themselves and everyone else that this does not apply to them. When you are part of the group that is against something bad, you are not bad. It's just another way to get supply. The criticism or negativity triggered them, so they attempt to control the other person's perceived opinion of them by asserting that they are against that same thing too, and this corrects the negativity they are feeling toward themselves. It really is all about them.
The way to protect yourself is to be careful of what you share and who you share it with. Pay attention to the people who seem to be attracted by negativity you might express and how they react. It's important to be authentic and speak your truth, but it's also important to pay attention to who is listening.