One of the answers as to why it is the case in Presbyterianism, doctrinally/practically not necessarily historically, has to do with frank acknowledgement that there are in fact ordered hierarchies in the world. There are some that are more fixed by nature (so, the parents are over their young children, e.g.); while our social-orders are allowed more variety.
In the church, Christ is the Head (which most acknowledge); but thereafter, are all men but a single rank? What of the apostles? Were they ministers of State? Yes; while the government of Christ is of another kind than all those of the Gentiles, it does not follow that there never has been "rank" to "pull." That's not the picture we get from Paul's letters. He says he did forego some rightful privileges. And he threatened and laid down punitive discipline. These are evidences he had rank; but he also had the humility of a foot-washer, which was one way Christ demonstrated the proper exercise of greatness in his kingdom.
If we have discerned the ordinary structure of the church by way of order: organization and rule, then we may ask the question of original jurisdiction. The Presbyterians concluded that a minister should be examined by his peers, equals in rank and responsibility, ability, and learning. It might be fairly simple for passing-educated laymen to judge a minister in a moral matter (guilty of adultery with a member, for example); but what about his doctrine? Someone questions the man's teaching, and he starts quoting Greek. "Oh, you don't know this? Well I do, so be still and learn."
Rather than split original jurisdiction, moral and doctrinal (and what if the line blurs?), it is sensible to place all original jurisdiction as it pertains to the minister with his Presbytery. Consider a simple "regional church," say a small city with four quarters/parishes, one congregation in each. All together, as Presbyterians we recognize not just the four, but the one church, which ruling council is the Presbytery. The body of ministers, together with the particular congregations' representatives, comprise that government.
We recognize that individually the ministers have their own charges, obedient to calls from the particular congregations. But as churchmen, they have peculiar concern for more than the lesser charge. And I don't mean that local elders (churchmen of a kind) do not have interests wider than parochial. But those not only typically have outside business interests, not making their living on the gospel as the ministers do; they have vested exclusive interest in the congregation of which they are members first, and officers second. Whereas, the ministers are uniquely situated in the church, it being all their business (exclusive of family, which is a calling common to humanity).
It makes sense for all four congregations, the whole church constituted under our hypothetical Presbytery, to have their government theoretically always existing and functioning, even if it must meet to be seen and do business. (Now, the Dutch Reformed only have that broader council in "existence" when they call a meeting, so there is no other place for a minister to have his membership besides the local congregation; but they also recognize that one church is but a part of the encompassing church.)
The ministers benefit from their collegial and formal connection, not that it should become a club and protection racket, but that they come together as accountable to the whole church, and in the interest of the whole. An expelled minister could not depart one congregation in the Presbytery, and present himself at another for a prospective call, not unless one of those congregations was presently in schism. This man already has no more standing in the recognized church (the association), perhaps having been completely handed over to Satan by his shepherding peers. Their duty includes warning the whole church as flock to avoid the predator.
Perhaps the above gives some answer, and fruit for further discussion.
