I think that's the most cases for those kid who were born rich, they're mostly sensitive because they've been spoiled since they born and maybe Ryan is one of them, that's why he's reacting like he was betrayed by Canelo and maybe that's the also reason why he revolt and find another one to train him.
Yes, he should definitely learn to be open to some criticisms and be used about the noise surrounding him because that's quite normal while you're moving up in the boxing industry.
Right, there are those certain people who are like that and sensitive enough when they are criticized publicly and for Garcia's case, that's his weakness and he should work on that one well because someday one of his opponents will use that weakness to get in his head and that could result in defeat.
He should learn to how to accept it until he get used to it and only pick some few criticisms that could help mold his character.