It's simple really, the battery is only rated to store X amount of power, but that doesn't mean it can't store more. You have X grams of electrolytic gel, and you know that 1 gram of this gel can hold an average of say 50mAh of power, then it's simple math to go from there. But of course sometimes it's a little more or a little less. We're not talking about something like a graduated cylinder which can only hold 100mL of whatever you choose to put in it before it overflows. You're trying to make this into a bigger issue than it is in an effort to save face, which is about as obvious as it is ineffective.
As for the battery discharging, you're actually correct, and this is why it is generally recommended that you don't use your laptop on AC power all the time. It will kill your battery much faster. Again, this is Li-Ion Batteries 101. As for why it's allowed to discharge like that is that it slows the process a bit compared to rapid minor recharges. This gets into how batteries work. The actual mechanics of how the power is transferred to and from the battery. I'd say you can read up on it yourself, but at this point, who are we kidding?
And apparently you're reading only selected parts of my posts, because I clearly stated that the swelling and exploding is a slow process that begins after the battery has been consumed. I said that the battery starts swelling if you don't replace a consumed battery, and that it will eventually damage the casing. It's really interesting when you see a MBAir battery start swelling BTW. The older MBAirs, not the new wedge shaped ones. Those have a different kind of battery. Should you then fail to act at that point, then eventually the battery will explode. I do believe I also said that this will likely take more than a year.
The exploding batteries of a few years ago were all made by Sony and due to a manufacturing defect. There have not been any fundamental changes in battery tech since then that in any way inhibits this sort of thing from happening. There is absolutely nothing about newer batteries that says a brand new, just out of the box, battery could not swell up and explode on its first use. The number of batteries that do this is small, but Apple and other companies would not offer warranties on the batteries if there were no chance of them failing. They'd make a big deal out of marketing the fact that the batteries absolutely will not fail, blah blah blah.
Simple fact is, like any other mass produced product, you'll get some of them that are just absolute garbage right from the start. Can't be helped, it's just a part of large scale production. Other times, you get a product that just seems to last forever. You could have two cars roll off the assembly line one after the other. One will be in the repair shop almost indefinitely, the other just needs the regular oil change and never has any problems at all. Happens ALL THE TIME. Doesn't matter what the product is, that's just the realities of mass production. And since they can't possibly test thousands, tens of thousands, or even millions of individual products, they use statistic sampling methods to do quality control most places. Every so many batches of a product are tested, and if more than some acceptable number are bad, they scrap the whole lot. But it could easily happen that just by sheer dumb luck, that one batch tested was the only good one produced, and a whole bunch of bad products go out. It gets worse in that these days, everyone in the supply chain pushes the quality control onto the person below them. So Apple has a contract with its various suppliers saying that they will only accept a certain percentage of bad products from them, and if that number is exceeded, then there are some kind of penalty clauses that kick in. So if a company makes resistors that they sell to Apple, then they have to make sure they meet those quality standards. So they then push the same kind of crap on their suppliers of raw materials. It has to be of a certain purity, etc. It's a corporate version of pass the buck.
Finally, before you go calling someone Mr. Right, you may wish to look at your own actions. You keep insisting that I am incorrect, yet I don't see any evidence that you have made any effort whatsoever towards researching the topic to ensure that you are indeed correct. You insist that you are right, and I am wrong, even though I seem to be the only one who can come up with any specifics. Before you insist that you're right and everyone else is wrong again, maybe you should really spend some quality time with Google trying to research the topic. If you can come up with some solid evidence that I am mistaken, I'm not so full of myself that I won't admit I was wrong. I highly doubt you'll find such info for any of the core precepts, maybe some of the tangential areas where I might play a little fast and loose with the facts because, well, they're tangentially related, and I don't feel like explaining things like why batteries do not hold a charge indefinitely.
So, if we don't see you back for a while, we can assume that you're either busy with your research or found out that you were the one who was wrong and weren't able to admit it.