I called you daft for not understanding the concept that someone who runs a swapping service station covers all costs related to their business activities and rolls them into what they charge for service, just like every other business does. I fail to see what is hard about this for you to understand. The answer to "who pays for X cost" is *always* "the service provider, with the costs indirectly passed on to their customers via the rate charged".
Really, you think that bad fuel can't damage an engine? It can and does. And it's the supplier who ultimately bears the cost. No, "bad electricity" is not a proper analogy (although your sarcasm in this regard is funny given how many devices are damaged by surges every year); a gas station fuels vehicles by insertung fuel into them, while a swapping station fuels vehicles by inserting pre-charged batteries into them. Batteries correspond to fuel in this context.
In what world do you live where car parts are regularly inspected by the manufacturer after being installed into the vehicle? Cars have hundreds if not thousands of parts more safety critical than a battery pack, and yes, manufacturers *are* liable if their failure modes due to damage pose an unreasonable risk of injury. Think of a famous failure case - say, for example, the Ford Pinto fires. Were the gas tanks defective? Nope. But the cars had an unacceptably bad failure mode in certain types of crashes, and it fell on the manufacturer to fix it - as it always does. A part must meet its use case, and if its use case is "deliver electricity from a swappable system and not burn the vehicle down if damaged", it has to contain the necessary safety systems to do that.
Lastly, you're still stuck in bizarro world where ICE vehicles full of combustible fuel are incombustible, whereas EVs with no combustable fuel and more often than not with batteries less flammable than a block of cheese (once again: *not all li-ions are the same*!) burst into flames left and right. Meanwhile, in the reality that the rest of us live in, the opposite is true. Heck, last summer I saw a flaming hulk of a passenger car with fire crews trying to put it out to extract the burned bodies of the two tourists who had been driving it. Meanwhile, Teslas and Leafs have been in many wrecks - go to Google Images and search for "crash tesla" or "crash leaf". Where are the fires from these oh-so-flammable vehicles? Yes, they have happened, but at a much lower per-vehicle rate than gasoline cars according to NTSB stats. Sorry, but your fire conceptions are just not based in reality.