Yeah, that's nice, but you need to get out of your head and deal with the real world instead. Nothing in this world is 100% certain. You might like to think your happy little Newtonian physics is, but the reality is you haven't done enough repetitions yet under perfect conditions to account for the random decay of protons in your subject material and are totally ignoring the fact that scientists try to eliminate error while doing multiple tests under ultimately less than perfect conditions and calculate an average and standard deviation, because the world operates on bell curves.
It is unethical and illegal to subject human beings to 'perfect conditions' for the sake of controlling all possible variables in research. People are far less predictable than "scientific" conditions. Apparently, the psychiatric community, among others, with its ethical review boards still has higher standards than you.
The psychiatric and medical communities don't claim certainty where none exists, at least not the way you do. In medicine you learn to deal with chance and risk. If someone has this minimum blood pressure, what is their risk of dying from heart disease? And, unfortunately, in obstetrics, if the doctor doesn't run an expensive test for this condition that the patient has a 0.01% change of having, and they end up having it, what is their risk of being sued?
If someone is shy, what is his risk of having an adverse social outcome? Is there a level of shyness at which the risk of having a poor outcome becomes significant? What criteria would meet that and what is the chance of a false positive or negative? What are the risks involved in diagnosing or treating someone for their shyness? Do the benefits of treatment outweigh the risks? Those are the kinds of questions scientists would be dealing with in researching shyness. You might not agree with them, but they're still a lot more serious than you think.
Shyness does not even show up in the DSM-V. The only hit on that site is a comment from 2005 that more research is needed to define the line between normal shyness and social anxiety disorder.
Proof? Your point about renaming/reclassifying pedophilia is absurd. In spite of hysterical blog posts from 2011 that copy and paste each other, at the professional level that discussion appears to have gone from one symposia at the 2003 annual meeting of the American Psychiatric Association (out of 104, so who knows what the attendence was) arguing that it shouldn't be a disorder, to a 2011 conference by an independent group, which boasted of 9 speakers and 38 attendees, that wanted it renamed "minor-attraction." They're marginalized. So, what renaming or reclassifying will the psychiatrists actually do? In the proposed DSM-V, "pedophilia" no longer requires someone to have acted on or felt impaired by the urges, and the renamed "pedophilia disorder" is the diagnosed act/impaired condition that they treat. Damn, man, talk about removing a stigma... Please, do some research, or address your own desperate need of oversight.
It is 100% certain your ignorance knows no bounds. Physics, Electronics, computer machine code instructions blah blah blah all have 100% certainty.
The quacks you seem to love to support have been ripping the public off for decades.
When you defend a fake profession that wants to eliminate or reduce the stigma of pedophiles you have show the rest of the world you have joined forces with some very sick and evil individuals.