We can assume that he was just told not to do so or might be, he thinks that if only he's not like that, there will be no problem that happened last December where he failed to show up in the weigh-in because of his viral condition.
Anyhow, trash talk or hitting the opponent with some offensive words is not really necessary.
They can do the talking on the ring, not in exchange of words in the public.
Yeah, maybe someone is the background is advising Casimero to tone down a bit because it doesn't make sense at all to trash talk the likes of Inoue and Donaire. The fight will happen sooner or later. And he should learn from his fellow Filipino, the legendary Manny Pacquiao, who chooses to do the talking inside the ring and not being so arrogant outside and talking trash to his opponent.
Let your fists do the talking and that would be looking much more better rather than opening up your mouth and trying to declare that you are already the winner even on pre-fight.
For sure there were people behind who do gave out some advices on making this behavior to be toned down so that it wouldnt create soo much hate.
In fairness with Casimero even if he's annoying due to his bad mouth or trash talking to his opponent he prove that he is not a loud mouth only but he can also dominate in the ring. But I guess this is just part of the tactic so that he will be known in the industry and can able to get the heads of more stronger opponent and he's actually successful with his current strategy.