It is hit and miss, but that doesn't mean it doesn't significantly improve the quality of life for the people taking them if a good balance is found. You try something and it doesn't work, you try something else.
My thirteen year old is bipolar, with paranoid schizophrenic tendencies as well. He's been on medication since he was eight, when he was hospitalized in a mental facility for trying to stab another child, writing obsessive and threatening notes to a female student and then trying to hang himself. He was eight. No reason for it, he's had a very stable life with lots of love and affection and no violence or inconsistency in the home. I know because I have had many home visits from psychiatrists and behavioral specialists as well as being extensively psychologically tested myself. He's tried to step in front of cars, he's cruel to anyone smaller than he is, was failing school and causing trouble there, the teachers were even afraid of him. One minute he was balling, the next he was raging at people... at least he was like this until he got put on one of the drugs you seem to think you understand and are discouraging people from taking. We found the right balance for my child, and now he's not at all violent, is doing very well in school, still has some minor issues with stealing things but he's not harming himself or others, he's not being as obsessive as he was, and he's actually smiling. I can tell when he doesn't take his meds in the morning, because by the evening, he's agitated and moody. His father (my first husband) was exactly the same way, but all grown up and it's definitely a chemical imbalance in his brain that causes it, because it is fixed when he is on the medication.
There are millions of people like my son, both milder and more extreme examples that are being helped by the drugs you are vilifying. It's not junk science, and some of those people would easily harm themselves or others if they were not on medication. To say that the drugs aren't important is to not understand the problem or the people having issues.
On the medication, my son is a functioning member of all of his social units, without them... he'll be in a jumpsuit... but whether it will be a psychiatric facility or jail would be anyone's guess.
You simply cannot just dismiss those kinds of drugs just because they have side effects because of the quality of life it gives my child and millions of other people like my child.