Eusebio Unzué is a smarter man than he is often given credit for, after all he has managed to stick it out in the sport for all these years. He's only been the team manager since 2008, but he served a long apprenticeship under Echavarrí. It's no surprise that he has inherited some of the traits of Echavarrí as a result. Echavarrí had a similar moment in 1996, with the cameras lingering at length on a Miguel Indurain who had had enough of a Vuelta he didn't want to be at and hadn't been prepared properly for; he had been dropped and was fed up, but due to his stature in the sport, plenty of coverage was provided of the great champion arguing with his team boss about his decision to abandon. Indurain never raced again. And Echavarrí was forced to choose between his team leaders after the flare-up at the 1998 Vuelta made it untenable that Jiménez and Olano could co-exist.
However, despite Olano having won that Vuelta, and being the logical pick, especially with much of the same DS committee that had managed Indurain's Tour and Giro wins still intact, Echavarrí sided with Chava, because Chava was his sentimental favourite. Echavarrí played favourites a lot. Not necessarily deliberately, but it definitely happened. And that's definitely a trait which Unzué inherited. I mean, just look at the way Joaquím Rodríguez was treated as Valverde's kid brother through his time at the team, and how much influence in decision-making at the team Valverde has had over the years. He just had a triple threat leadership committee and, when forced to disband it because they could no longer coexist, he chose the guy in his late 30s who hasn't won a GT since a solitary win a decade ago, in a tamely raced edition where he was one of only about 3 riders to target that race specifically because at the time he had no choice in that matter. The core team matters to Unzué, and he likes going with what he knows. It's why he likes internal hires - people like Lastras and García Acosta becoming guys in the cars as soon as they hang up the cleats - and retreads - rehiring guys he knows from before even when they're past their prime, like Moreno, Plaza and Karpets - as well as rewarding loyal long-term servants like Erviti and Rojas and giving them first dibs on the calendar. They also largely like to bring young riders through from their own feeder system, and this has served them well even if they have to bring them through slowly once at the pro level. So it's a team where seniority and tenure wields power, and the team manager is keen on reinforcing what he knows.
He also has had to deal with a good few flaky, inconsistent riders, and overly-emotional, heart over head racers in his time. Which is not in and of itself a problem - after all, we all knew Supermán's reputation prior to his signing. We've all seen him win brutal MTFs, and collapse completely, we've all seen him capitulate in time trials at the beginning and the end of races, we've seen him lose his cool and argue with people in a group with him, we've seen him agitate and ruin chemistry in a chase, we've seen him lose his mind entirely and assault spectators. He'd had his fallings out with the Movistar guys before signing, too. But the thing that makes this so weird is that until now, the relationship had worked well. Almost too well, in fact. The team were patient with him while Coronavirus impacted his training, they worked for him in the small races to bring him up to speed, and he in turn was willing to stay in the Tour long past the point at which he would have been justified abandoning, as the team needed what little help he could provide as a domestique for Mas, and he and Mas had been working well together in the Vuelta thus far. The one-year experiment had been deemed a success and he had come to terms on an extension. And then, almost as soon as everything seemed to be looking up and the team had solved the co-leaders problem, a bomb goes off.
Now, considering the miserable time he had at the Tour and the work he did for the team, and how he had patiently played his side of the game in the Vuelta, did he feel that he was being palmed off as a #2? That the team was paying lip service to a 1A/1B scenario but was proving themselves solidly behind Mas despite him having got that win in the queen stage? Hard to say, but we know MAL is short-tempered and we also don't know what was said. Potentially some words from the team car about tactics veered too close to a personal slight for his liking? If we actually did have Unzué micro-managing, going above his DSes and giving MAL the instructions personally, then yes, I can see why that would send him over the edge. Because if he already feels the message is that "you aren't as important to us" in a team where we know there are favoured sons, having Unzué instructing him directly over the head of his DSes also sends the message "I don't trust you to follow orders" as well.
It's quite likely, once all the dust settles, that this is largely built out of a combination of misunderstanding, pride and frustration. After all, you have a team with history of struggling to juggle multiple leaders and long list of questionable tactical decisions, giving a questionable tactical instruction to a volatile and temperamental rider, who has been hired as part of a multiple-leader setup and is on a bad day that will likely be made worse by this decision.