I think it's that people are trying to diagnose things that, most of the time, it is impossible to get to the root of. Say you have seasonal depression, but to you it just seems like it's an everyday malady. By the time you feel compelled to see someone, you may be so frustrated that you don't even realize it's not constant. So you may get misdiagnosed with either bipolarity or chronic depression. You also have people who, perhaps on a subconscious level, want to hide that they have an mood irregularity or any other symptoms of disorder. Seeing a psychologist once likely won't be as telling as their long term behavior around people they trust, but it's not like you can interview their relatives.
You can also be completely normal, but still be a d**k. People can diagnose you with a borderline or narcissistic personality disorder, but in reality you may actually have empathy / understanding of peoples' emotions and know that you're being a d**k to them. The results are the same though if you just don't care, and a careless psychiatrist may not notice.
I'm also not surprised that people have anxiety episodes. We have high stakes exams throughout our education, and the majority of the people on anxiety medication (under the counter or prescription) are students who are just trying to get by. What would actually help them is change in curriculum and universities / public schools giving them instructors that actually want to teach and are good at it. People shouldn't be staying up several nights in a row to finish their homework or to study for an exam. If the exam material is that intense, it should be broken down into portions rather than just become material you cram for and then forget after summer break. You would have more exams, but the stress load may be less exhausting.
It also depends on what offices you go to. There are those that are for the public and are paid for by your tuition or by some other nameless entity / organization. After a while, they may just want to get you out of the door and declare you mentally healthy. Real psychological therapy could take years, but some psychologists don't have that much time or are unwilling to, so they refer you to psychiatrists who can diagnose you and prescribe medication.
I don't think children should be taken to any psychologists or psychiatrists though. They just need to have better parents who aren't afraid of them and are willing to tell teachers / professionals to ******** off. If after their formative years, where they actually care about peer assessment and fitting in, they're having trouble adjusting or develop some symptoms of depression talk therapy might be best. It's better than just letting it fester until they're adults and develop some weird perception of themselves or suffer from emotional scars to their self esteem.