I will be the first to admit that there are some refs that don't do themselves any favors. But taking it upon yourself to attempt to publically humiliate another human being does absolutely nothing positive.
1: It teaches your kids a lack of respect for authority. You think your kids will always have great bosses? Why don't you just teach your kid "If you have a bad boss, fuck him, and tell it to his face". It does not matter if authority is wielding its power ineffectively, Authority is authority, and you will not get far in life if you throw a temper tantrum everytime you think you could have done something better than your boss.
2: It teaches your children to "tilt" when faced with adversity. Harassing the referee just takes your kids focus off soccer. Instead of trying to win, some kids become more obsessed with counting how many fouls the ref calls against them. I see it all the time. You think they can mentally stew on referees mistakes and then be able to track the man he is supposed to be marking from his peripheral vision while making a heads up counterattack? No.
3: The bad referee is just going to view himself as a martyr and become further set in his ways. If a referee is ever going to be told he did a bad job, it will most likely be by one of his peers and it most certainly will not be said in public. The last person a referee will ever have an "aha" moment from is a pissed off parent.
4: It detracts from being able to enjoy potentially good game. Self explanatory.
5: It makes you look like a child. No seriously. Search "bad referee" or any other derivation in YouTube and find me a video where the parents comes off as looking better than the referee. There isn't one. Even when the referee completely missed an obvious call, somehow the parents always look like more of a whiny ass.
I have never seen a referee make a call just because the other teams asks for it. It may seem that way because 1: there is actually a literal amount of time it takes to physically bring the whistle to the mouth (jesus parents). 2: Referees are waiting for advantage 3. The referee has no clue what happened and is looking for clues and is replaying the play in his head 4. He is human and is trying to remember which way red is attacking this half.
Calm down, cheer or shut up, and watch the game.