Hi @SteveDoesJapanese , first off sorry for the confusion! This topic is something that we wanted to, and still will, cover in a higher level. As passive verbs don’t fully explain how these verbs work in Japanese, we chose to give them a term that we could reuse for each of れる and られる’s 4 different uses.
A lot of people seem to also like ‘receptive verbs’, as that covers the meaning of 受け身 ‘receiving an action’ really well.
The reason we chose ‘displacement’, is because it is a bit more of a broader term that fits with all 4 categories of れる and られる. Those categories are:
受け身: Receiving an action.
可能: Being possible.
自発: Happening spontaneously.
尊敬: Respecting another.
This becomes ‘displacement’ because they all shift the focus from the one thing to another. Basically like the following:
受け身: Shifts focus from the thing that had something done to it, to the thing that did it.
可能: Shifts focus from the possibility of something, to how that possibility came about.
自発: Shifts the control over some specific action away from the subject.
尊敬: Shifts the focus from the speaker to the person being spoken about, in order to show respect.
Realistically we could have also called them ‘focus shifting verbs’ or something similar, but displacement was the term we ended up going with. This is a super brief explanation of how られ and られる are ‘linked’ in all of their meanings, and we still plan to go into more detail about this in the future. It’s one of those topics that becomes much easier to understand with a picture .
In any case, I hope this wasn’t totally useless information!