It is not an accusation at all, just do a bit of research and you will find the answers. Btw, totally fine with this since that's how the world works. He got to the top with his incredible business acumen (timing was great as well of course). Once you are at the top, you can bend rules a bit into your favor.
What you're saying doesn't make any sense. If he had the wherewithal to enter into OTC contracts then they were exactly that, over the counter unique contracts between Berkshire and the counterparty the terms of which were unique to each contract which obviously didn't have a mark to market clause that would have forced liquidation. The entire structure of Berkshire's risk management is based on the risk of each of these contracts, so obviously they would have structured their investments in an entirely different manner if they faced an entirely different risk setup, so it's idiotic to say they would have been forced into liquidation. One wonders from your comments if you actually understand what an OTC contract it? It's kind of like saying, "If Walmart had to buy stuff at the same price as the commoners who shop at their stores they'd be bankrupt by now"! Not only is it not an apples to apples comparison but it displays a fundamental ignorance about the underlying economic concept.