I spent most of my life starting colts, many different ways, depending on what colts and what the stable/trainer wanted.
I watched that and the colt had been handled before plenty, was not a watchy, spooky feral horse, that was in the colt starter’s favor.
He also had help, that he didn’t really use that well, the help was a bit late, not that good timing and irregular.
What he did there is what we call “steal a ride”, not really teach thru different measured steps and eventually get a saddle and a rider on without fireworks, but smoothly, as if the colt had already been under saddle before.
You can hurry all as he did there and most times get by fine and have many colts going on more or less, but you also create resistances and a colt that is overwhelmed and wondering what happened, not one that has learned progressively to think about what is going on.
Those colts take long to relax, they tend to hold their breath, you can feel their hearts beating, they are stressing.
In settings like he was there and horses like he has there, really sweet ones, I would have longed a bit smoother first, then maybe get on without a saddle and someone longing the colt forward.
The add the saddle and keep the colt going without giving it a chance to try to hump up, that was totally unnecessary resistant motor memory the colt learned there.
Then get on with the colt saddled and someone still longing the colt, as it then knows to go forward on the longe line and it is under some control, for a few minutes, before turning it loose.
The fellow was a little careless when he didn’t notice the colt was resisting and eventually reared.
Any time a colt acts up, it is a black mark on the handling he is getting.
Enough will happen that can’t be helped, not good horsemanship to let it happen unnecessarily or worse, provoke it.
That fellow sure was limber, that I have to say, but also may cause some bad habits, as he knows he can get out of the way if things go South and so at times is not as careful as he should be.
I assume that, if the colt had been different, he would have worked him differently.
He did what he did because that is what he could do with that colt.
I know that I did more sooner with some colts, a few I took extra long also.
As our old riding instructor kept repeating, always pay careful attention and utterly respect the horse first, all other will then fall into place.