You are correct. Those are "Idiotic Rules". I have hunted wild hogs in TN and once saw a large boar that was killed by my buddy. When we went to the taxidermist to have the head mounted, he found a 38 spl slug embedded in the boars skull right between the eyes. It had healed around the slug. I witnessed this first hand. While I have seen 1000 lb bulls dropped on our farm with a single round from a 22lr to the brain, this was done at contact distance for slaughter and we cut its throat as well. The 22 was just the knockout blow and is not a good choice for large game.
A 200+ lb wild boar is a tough animal and can be somewhat dangerous when cornered. A 22 WMR will kill one if the shot is well placed but... If not, you will find yourself facing a large, scared, pissed off, wounded animal and that is unpredictable and dangerous. You will need max penetration. I am guessing that the 40g FMJ if the likely best of a long list of BAD choices, in this case. A jacketed soft point is next. Avoid the hollow points as they might not drill deep enough through these large beasts to do any damage. Keep in mind that while shorter and more compact, a wild boar can easily weigh in twice as heavy as a whitetail buck. If you shoot one, shoot it again immediately. Then give him the old pig sticker with a large blade knife. Thinking Gerber BMF and similar blades. Hunt close enough to trees that if charged, you can grab a limb and tuck your legs up high enough to allow the pig to pass underneath you. Have fun and be safe.
Irish
PS: I once shot a 325lb boar with a .308, 165g Nosler ballistic tip at a range of 5 feet. It was a perfect shoulder shot that penetrated both lungs and wrecked all the plumbing in the top of the heart. The boar did not flinch and proceeded to fight with three hounds and then run for about 40yds before reality finally let him know that he was dead. Remember this when you are about to shoot your first pig with that 22, lol.