The reason I stated my experience was not to validate the field, but to illustrate that people have different experiences. The most personal I can get with it, is if I were not prescribed the medications I were given, I probably would have died within a year or two. Does it validate the field totally? No, but it gives it credit. Just as your experience removes credit. What it does point out that it's neither purely good, or purely bad.
How am I wrong to think that it's well regarded by the medical community? If you want to take the stance that an internal view within the field is not reliable, sure that can be fair and I can see why people don't trust internal reviews. Still, it's regarded because there is lots of scientific and medical evidence published in journals, reviews, and government reports that show the benefits and help increased health in those who receive it. To be more specific: when a medication for psychiatric disorders goes through clinical trials, it has to clearly demomstrate a remission of symptoms in individual afflicted with the disorder it's trying to mend. If these things couldn't be shown, the field would collapse. That's what I mean by well regarded: the field helps people, and data backs it up.
The question them remains what the amount of harm it causes is. Currently there is little data on this to my knowledge beyond failed clinical trials, which doesn't differ signigicantly from standard medical clinical trials. You are correct that most of the issues you experienced were due to human nature/error, and that is honestly something that is really difficult to solve, and is sort of a separate issue from psychology/psychiatry itself. Even if we do have a more rigorous scientific understanding, and a much more efficient diagnoistic system, it still wouldn't completely resolve the human issue. It sucks but it's not a fully solveable problem.
Ultimately though, you do lack solid evidence beyond your personal experiences. You're the one being critical and thus bare the burden of proof. Most of your proof is philosophical, experiential, and anecdotal. It goes insofar as to (as said previously) point out flaws, areas that need to be fixed/resolved, and were people need to have a critical eye. However, it does not bare enough to trounce the hard data that psychololgy and psychiatrty has.