I'm reluctant to say why staff might demote a bureaucrat, as it's rather complicated on all and likely taken on a case-by-case basis . . . I'd say that things such as death threats, constant copyright violations, and impersonating staff members would result in very likely demotions.
There's other reasons, for sure, but I would say that if you have a specific issue with a bureaucrat then there's a line of action to go through, which I - or someone else - could send you . . . this starts with trying to resolve with said bureaucrat, with talking to staff as a last resort (or a first resort in case of death threats or severe abuse/harassment).
You can also ask in the forums with specific types of behaviour, perhaps examples, so that way people could give you more specific advice, too.
I had trouble talking to Hey1234, admin of Disney Wikia. He rebuked me for my statements. He thinks they are nonsense.
Most of the Terms of Use is a bit murky. What one person might consider a violation, another might not. Words like "obscene" are open to interpretation.
He won't likely get demoted for that.
To be honest, I agreed with some of what was said (at a glance). It just seemed that the two of you argued over semantics and he blocked you for a very short time, and now you're allowed back on the wiki, with all having been resolved. If we keep this strictly on-topic; staff are very unlikely to intervene based off personal disagreements, and he doesn't seem to have broken any ToU (that I know of as a regular user and not a staff member).
I'd personally advise to let it drop, as it might cause more drama by going over and over the issue and aggravate the bureaucrat in question, but - if you can't - you can always politely discuss it with him, providing you stop if/when he asks you to stop. Often, these things can also be resolved with polite discussion and each side listening to the others' points.
Maybe you look into Disney Wikia and into my message to him, then you'll know what I mean.
I will say this in their defence:
There is a difference between 'jealousy' and 'envy', and your change wasn't grammatically correct, as you can't end a sentence with a preposition. You also seem to be messaging them a lot, including not giving them time to reply, sometimes persisting on demanding a reply only a few hours after a previous message (which would be annoying, when they are likely busy and can't respond simply as you wish for a response).
A few messages of theirs were removed; I'm not a staff member, and I'm struggling to find what was said in those messages due to layout and so forth, so I don't know if maybe they were rude or abusive to you, or even if it was another member that intervened.
I will say this, though . . .
Bureaucrats don't have to listen.
Is that fair? No. Is that how wikias work? Kind of.
He's told you that "this is a rule, please don't argue", and so you can't really argue with him, when he has expressed that he's not willing to budge on the issue. I know it can suck when you feel you're right, and it can be infuriating, especially when you know the other person won't hear you out, but . . . life can be like that. You have to let things drop sometimes, else you'll be stewing in resentment for a very long time.
I assume that you don't know that envy is synonymous to jealousy, do you?
I have an English Literature (Hons) degree.
First link on Google: https://www.diffen.com/difference/Envy_vs_Jealousy
I could also send you a Simpsons link, as it's permeated pop culture to be referenced.
This is getting off-topic, though.
tl;dr The only person that can demote an admin is a bureaucrat or staff member, and the only person that can demote a beauracrat is the beauracrat themselves or a staff member. The beaurcrat in question seems to have broken no ToU and had a fair point, so staff likely would not demote them. It's better you just drop it and move on, for your own peace of mind.