I don't like these forms either, because what they are trying to say is that even if the company is grossly negligent, to the extent of handing me equipment that they know is faulty, or just not counting me back on to the boat and leaving without me, that if it goes wrong and I end up bent/lost at sea/drowned or otherwise hurt or dead, it's not their fault.
I have actually had a dive boat give me a BCD with a leaking inflator hose, causing it to self-inflate. When, after nearly going into orbit from 28m down, I took it back and swore at the instructor who asked how my dive was, and explained the problem he said "it wasn't the orange one was it".... Shame they hadn't told the other guy handing out the gear about this little foible it had. Ok, I should, when I started having trouble staying neutral have realised a bit quicker what the problem was and disconnected the hose. And my buddy did solve the problem - though it took him yanking the purge valve nearly out of the thing to get it to deflate.
But it just seems logical to me that if the gear is known to malnfunction and do something dangerous (and not obvious on a pre-dive check), you might want to not hand it out to a customer, particularly when you're a 2 hour scheduled flight from the nearest chamber, and if you do, you might be thought to have some small smidgeon of responsibility for the results.
Absolving a dive operator of liability where I dive too deep or come up too fast, put my hand down on a scorpionfish, tickle a shark, or even where I dive the limits but get an "undeserved hit" (even if they "let" me drink too much booze the night before) fair enough, absolutely, my fault, and I'll insure for that. But giving someone a license to kill me seems a tad much.
Perhaps that's because I live in Britain - you could possibly ask me to sign that waiver here, but you wouldn't have a hope of relying on it in court. And the last PADI waiver I signed here didn't even try to waive liability if the shop was negligent.
Then again, most damages here are decided by a judge, so tend to be lower than some other jurisdictions.... Then again, you only get damages for "pain and suffering" if you survive - if you're a corpse, they only pay for the funeral and loss of earnings to your dependants. So us single adults are cheaper to kill than to maim!