Seems to me the reason these rooster threads become so contentious is because there just isn't any one size fits all best way to deal with cockerels/roosters.
There are show, game, pet, production and hatchery bred birds, with completely different temperaments depending on how carefully they are bred.
Birds that weigh anywhere from 2 to 20 lbs, some that can REALLY hurt you, the others not so much.
We have roosters housed by themselves, in small breeding groups, in tiny TSC coops, in spacious pens or pastures and free range.
They might have 2 hens or 200 hens to themselves, they may be the only rooster or there are lots of different roosters and cockerels, pullets and hens around. Some have plenty of room, others are all crammed together.
Some are babied and snuggled with and handfed from the day they are hatched, others come up hardscrabble getting their butts kicked everyday by other birds and/or humans, having to fight for their food and position from day one. Then there are the lucky ones that get to grow up just being chickens in a plentiful, stable environment.
All these birds come from a different place and have vastly different attitudes based on how they were bred and raised up. What works for one rooster, might not work at all for another rooster in a different situation.
IMO the main thing to keep in mind when dealing with cockerels is that there's not so much going on in those tiny little brains as some people seem to think there is. They didn't suddenly turn on you, they're not plotting against or out to get you, they don't hate or love you, for the most part they aren't even thinking about much of anything, they are just acting on instinct.
No need to get your feelings hurt, wage war against them, or institute any elaborate training programs. Let them be a rooster and do what roosters do, if for whatever reason they become dangerous to humans or other animals, eliminate them, no muss, no fuss.
In my short experience, you are bang on with this assessment! We have a 30 week old cockerel that was handled his entire life, but when he turned 26 weeks he suddenly turned into the protector of the flock. At first it was a shock that our little guy would suddenly turn on us, but the term "bird-brain" is all that was happening. They are running completely on instinct, and don't love or hate anyone. Once you come to the realization that they are a primitive animal, it is a lot easier to deal with the change.
The approach I took was to make him lower on the pecking order than me. I would make a point to lightly hold him down (in front of the hens), and make him submit. All it took was 2 days of submitting him to let him know that when I'm around, I'm the protector. When I'm not there, he is in charge, and he does all the regular rooster things (calling the flock in at the end of the day, and chasing off the neighbors cat).