I think this is a common scenario but few are aware of it, on either side of the equation. Having grown up with a packed 8th house and a parent who had Pluto opposing the Sun, I can you a lot about this. A person gets to feeling bad and they’ve just got to degrade someone near them, it’s a survival mechanism.
You can see this clearly, when someone launches venomous attack against a loved one or an associate or even a celebrity they’ve never met.
If a person does this, it’s their problem. But it is also the problem of the person they degrade if that person internalizes what is said about them.
Have you ever seen someone mad or disgusted with themselves be mad and disgusted with you? When you are venting your spleen on someone, do you ever consider the idea that you might be the shadow figure? (My guess is no)