I'll try! But of course this is ONLY my opinion
Horses, like persons come with different temperaments and personalities.
I may be wrong since I don't know him, but Tintero strikes me as a classy and sensitive horse and that kind of horse is the easiest to ruin, specially by amateur riders (sometimes also by the pros).
Why? Because amateur riders make mistakes, and those mistakes make the horse make bigger efforts than he should, or are painful for his mouth or back, or scare him.
If you go very slowly in your progression, you'll have better chances not to ruin your horse, because you will be strongly confirmed in a certain level before you take the next step, and thus you'll make less mistakes when the jumps are higher and the courses more complicated.
If you ride a less complicated kind of horse, maybe less classy, but with a stronger head and moral, and big muscular strengh, less sensitivity, you'll also have better chances not to ruin him: those horses usually are more forgiving and forgetful with their rider's mistakes.
IMHO Charlotte has forsaken those 2 conditions. She's been riding a senstive horse and she's tried to progress too quickly.
Last year she had rather good results with Tintero. Why? Because Tintero was jumping courses way bellow his capacities. He used to be a 1'50 horse. 1'15 and 1'25, even 1'30 were nothing to him, and that's why he was such a big help to Charlotte.
The problem was that Charlotte got those good results because the horse was making most of the work. I didn't see all of her jumps but I remenber several bad courses that she nevertheless finished at 0 faults.
She took too many jumps from too far away, which makes the horse make a big effort and usually hurts his mouth since the riders hangs too much to the reins.
She took too many jumps from too close, which makes the horse make a big effort and may hurt his back and his back.
Also, let's not forget: at the end of the day horses are shy fearful creatures. Given the option, in the nature, they would never jump a 1'30 fence, they would much rather go around it! They jump because they are trained to do it and because they trust their rider and trust that nothing bad will happen to them.
BUT when a horse has had too many frights and bad experiences the trust began to desappear. He is not sure anymore that he won't be hurt, and he is not willing to obbey someone he doesn't trust. And thus, horses start to refuse the jumps. If they feel the rider has doubts, if they think the jump is too far away or too near, they just won't jump.
And so, the same way their first months Tintero made Charlotte better than she was because he mended her mistakes, now he makes her worst than she is because he doesn't allow even small mistakes than other horses wouldn't take into account.
The 1st symtom that something like that was happening was that at some point last year, Charlotte's results with Tintero began to get worse, but there usually was an improvement when she had been on holidays or travelling and she went back to competition. That probably meant that in the meanwhile someone else had been working with Tintero and restoring his confidence.
Many "ruined" horses are never recovered. They may improve somewhat from their mental insecurities but they will never be the same. Others, can be fully recovered when rode by the right person. Rozier and Charlotte probably think Tintero is that second kind of horse and that's why they are still working with him.
When I think about why is Charlotte has acted like that I only find 2 possible answers (maybe there's a 3rd one I just can't put my finger on).
1. She doesn't fully realize what's happened.
I think it makes sense because the same way that last year she was totally full of praise when talking about Tintero, in the vogue interview she seems a bit disenchanted with the horse, and most surprising she puts all the blame on him, as if she had no fault at all!
It does not seem so crazy because I've bee having the feeling for a while that Charlotte is surrounded by too many shameless flatterers whomust be repeating her all day how wonderful she is, how she is the most talented equestrian, the most intelligent student, the most beautiful woman... It's no surprise if she kind of looses touch with reality. If they counseled her to buy an unnecesserely expensive horse (I wonder how much money they won in the transaction!) they will never admit in front of her that she isn't a good enough rider for Tintero and more important, that they gave her a bad counsel.
2. She doesn't care if the horse is ruined.
Why? Well, they are 2 main reason why you usually worry about ruining your hourse. First and mainly because most amateur riders own only one horse and they develop very deep relationships with them, they love their horses and don't want to hurt them. But also, because if you ruin a horse and you need to replace him to keep competing that costs money, and most people can't afford it. Charlotte can afford to ruin one, two, three or four horses in her learning process. She doesn't need to wait until she feels sure in a given level to go step higher. And with any new horse she will have less trouble than with the last one because she will have improved a bit (we hope).
Now, she doesn't strike me as a person who will behave like that. She seems sensitive and caring. But also a little bit out of touch with reality, she may think that if the horse doesn't follow her he is not good enough for her. And I really don't know anything about the Roziers philosophy and training methods. They aren't among my favourite riders but I don't know how caring or patient they are.
Who knows? Only time will tell, maybe I am completely mistaken.
The only thing that strikes me as totally weird is that Charlotte and Charlotte's friends insist all the time in how she is such a perfectionist. Someone (sorry I don't remember who) wrote in the current events thread some days ago, how she found it weird: a perfectionist doesn't abandon her studies midway.
I don't know, maybe she does if she can't stand the stress, but the really weird thing is that a perfectionist certainly doesn't burn stages and skips steps. If you are a perfectionist you don't want to go to a higher level until you have perfected the lower one. You don't want to go too quick with your learning process because you hate making mistakes and doing things any way.
And yet, Charlotte doesn't seem to have a perfectionist attitude at all in her jumping career. She jumps 1'25 courses when she still makes evident mistakes at 1'15, and she goes to 1'30, even 1'35 when she still has often trouble at 1'25.
I am not saying it is something that weird per se, but it's not something a perfectionist would do.
And, WOW; this is the longest post ever!
