I've tended to passively watch such discussions in the past. I really only get involved in maintaining computer security, but you cannot begin to understand security if you do not start with understanding what an attack vector is. And you cannot understand that without seeing how the problem is tackled.
That's the first element in all this - from the perspective of the engineer on either side, there is a problem and there are anywhere from zero to infinite solutions. The morality is a social construct - an important one, but not one that the lock cares too much about. Something works or it doesn't. It's all covered in The Magician's Nephew.
The second element is what you do about those solutions once you have them. (Of course, you can't do anything about them until you have them.) This applies whether you're in this for sport or profession. Once you've mastered a lock, be it Yale or Kryptonite (yes, that is a brand), it's going to get boring very fast (to those in sport) or troublesome (for security engineers).
There's only one answer to that, build a better lock! Design a lock and key that will work easily (so it's practical) but where the flaw you exploited is absent. Those familiar with the British TV show The Great Egg Race will be familiar with such projects. Scrapyard Wars did something similar, but not quite as well IMHO, as The Great Egg Race was limited to common household items. Besides Prof Heinz Wolff was without equal in eccentricity and style. Only thing that could have made it better would have been adding Richard O'Brien.
Anyways, the bits and pieces around a home are ample to construct, and experiment with, different lock designs. Though to be able to test the design properly, you'd need to have metalworking tools to construct a model suitable for testing rather than the loose assembly of junk that was the prototype.
Why does this matter, if there are locks you can never defeat? Because, really, when you get down to nuts and bolts, you know there are always exploits. Perfect locks do theoretically exist, but even if someone designed one, it would be too expensive to produce. Complexity reduces reliability (unless you add extra quality control) and introduces new ways exploits could occur (unless you add extra testing).
Doubling complexity quadruples the quality control AND testing required, but only increases security a diminishing amount each time. Consumers won't pay insane prices for a lock thats only 0.001% better than the cheap one next to it.
So you know the lock can be beaten. All you have to do is get into the head of the designer. Engineering is methodical and systematic, the laws of physics don't vary, so if you can design a better lock, you're halfway to knowing what a "better lock" even means. From there, it's analysis all the way. You know the why, because you discovered that with your own experiments. You know the what, because you can look. The rest is just cryptanalysis, how to turn your knowledge into a pseudo key.
Electronic locks are an exception only because the DMCA forbids you from knowing how they work. Even where no similar law exists... well, just look up DeCSS Jon Johansen's terrifying treatment as an example of what happens even when such examination is protected by law.
However, what you do in the privacy of your bedroom should be ok.
RE: Why is lock picking so much fun ? ? ?