I've already admitted that I didn't previously consider human to human transmission to be the primary focus of pool sanitation, in particular the survivability and transmissability of fecal-oral viruses surprised me. Unlike many a pseudorationalist, I readily admit my previous lack of knowledge / foresight. From the data you provided, it does indeed sound like a rather bad idea to use ocean level salinty in a public pool. (Though I was never thinking about public pools to begin with.) This does not justify the torpedoing of the entire concept, any more than the bladder cancer research means we should abandon all discussion and approval of chlorine. Anyone can quote statistics; the real challenge is in connecting the positive to the normative. Well no, I'd say the real challege is to intelligently interpret all data involved, and not just the ones you agree or disagree with. (Which was the only reason I brought up bladder cancer.)

So, there is still the unaddressed question of hypersaline concentrations (the extra buoyancy would be pretty fun too), and the completely different scenario that home pools present (half a dozen mostly related people who are already touching the same doorhandles vs. thousands of unrelated visitors every day.)

Thesis statement: Salt, along with some other metals, (bismuth ftw if only we could find some large deposits) has a number of extremely attractive qualities: relative lack of adverse human health effects, low cost (don't quote me tiny, overpriced bags of purified retail stuff), and the permanance / lack of maintanence because yes, people are lazy and stupid and real world risk analysis does not simply ignore operator error. It is foolish to ignore these qualities and write off the concept because:

1. OMG SALTWATER SHOULDN'T BE DUMPED ON THE GROUND (I think well publicized incidents of stupid people poisoning their own topsoil and wellwater will help drive this point home. Fortunately, there are plants like Salicornia to help with the cleanup.)
2. OMG SALT CAUSES RUST (meh, steel is overrated and overused anyway. composites ftw)
3. OMG SOME STUFF CAN SURVIVE IN OCEAN LEVEL SALINITY (see above)