The bottom line is that many clerics do not like independent priests because they can't control them. That lack of control terrifies them.
What about the Bishop's grave responsibility before God for the priests they ordain? How about you look at it from that angle?
When a bishop ordains a priest, that priest now has supernatural power and dignity. He is now a leader, a teacher, and a vital source of guidance, truth, and the sacraments for the Faithful. A rogue priest could do *great* damage, cause divisions, destroy souls, etc.
Consider that such grave power and responsibility is a SERIOUS temptation for any priest who isn't already in the Unitive way (the highest of the 3 stages of the Interior Life). Temptation to over-socialize with Faithful, temptation to take worldly "consolations" here and there, temptation to avarice, gluttony, sloth... pretty much all 7 of the capital sins. But as a priest, he has opportunities and doors opened to these vices that *aren't there* for the majority of the Faithful. He is in a special place of authority and revered by the Faithful. He is a special kind of guide, leader, and confidant. He hears confessions and gives spiritual direction. He has opportunities to fall with women (for example) that the average layman does not. He is a single man with lots of free time and usually above-average brain power; this can be a problem. A priest can go in any of a thousand directions. He can be an amateur scholar, a TV watcher, a gossip, a wine expert, a Chant expert/nerd, a modern day Don Bosco -- all sorts of things good, bad, and in-between. And Heaven help him if he hasn't conquered all his faults by the day of his ordination.
And let's keep a Catholic perspective: the devils target priests more than anyone else.
And then there's the simple fact that a bishop is responsible before God for every priest he ordains. I'm sure many good bishops have been taken off-guard over the years when they find out just who they ordained. God alone knows, and God is the Just Judge. But nevertheless, a bishop must do his due diligence.
Some measure of control over the priest he ordains is actually a good thing, a Catholic thing, and a traditional thing. The idea of "independent priests" is completely foreign to Catholic thought. Have you ever been to an ordination? Remember the part where the priest puts his hands inside the ordaining bishop's hands, and promises obedience?