They're saying that a person who is bureaucrat can choose to step away from that role.
The "beaurcract themself" just means that "the person who is a bureacrat", as in like they can resign from the role, but they still cannot demote other bureaucrats.
You mean" those who do not wish to be bureaucrat they'll resign, and they can longer demote another bureaucrat?
Not quite . . .
Okay, say you and me are both bureaucrats.
I cannot demote you and you cannot demote me.
If I wish to demote myself, I can. I can remove myself as bureaucrat and resign, which means I'll no longer be bureaucrat . . . you can demote yourself, too, but we just cannot demote each other.
As Tupka said: staff members can demote bureaucrats.
Wiki managers are staff members.
So wiki managers could - theoretically - demote bureaucrats.
Demeaning behaviour and unreasonable attitude?
In itself, no. Because those are not objective traits. But if the community thinks so, perhaps.