Compare it to soccer where there is also a lot of whininess in the complaining about calls.
It's become accepted that vulgar, angry, disagreement is acceptable until it goes "too far".
Tantrums are just socially accepted in baseball, and some other sports.
Probably being born from public schools, and teachers being the referees, they don't have to take any nonsense from players and can take the ball away from you, lose you ground you have gained, or card you if are abusive to the referee.
Abusive parents on the sidelines can result in sanctions on clubs.
Even if you think the referee made a bad call, it is never acceptable to be abusive to match officials.
It blows my mind the things I see in football they allow people to get away with.
One other offshoot of rugby officiating is they will admit wrongs and they'll say things like "I didn't see that." Compare that to the NFL where the refs make a bad call and the league will back them up to the point of being ridiculous by reinterpreting the rules to make the officials right (see "not a catch").
Rugby is so refreshing.