This has been a societal shift over the past few decades and it is by no means exclusive to All Star Cheerleading or sports, in general.
A lot of it has to do with parenting, perceived entitlement, and lack of responsibility/accountability.
Not to mention, as a whole, honor and perceived social consequence have disappeared---for example, if I took my child out to eat in Germany and she screamed her head off I would have been told to leave (not asked, told), in our country not so much. But moreso, unless I was with family or friends no one would really know if I let my kid scream in a restaurant, or pee in a Playplace, or take down a aisle worth of toys at Target---I'm not held accountable for my actions socially because my town is big and I rarely see people I know out. 50-60 years ago, if you were improper or acted socially loose, the whole neighborhood knew about it and you were talked about or worse, shunned. The need to keep your children 'in line' was demanded, now not so much...