This is one of a set of old
DVC perks that does not scale well.
When there were many fewer DVC members and a small handful of DVC resorts, most of which were separate from cash hotels, hopping was workable. Now it's not,even without any rule bending, stretching or breaking.
If it were to be restructured I think it should be set up differently as a limited perk among DVC resorts in close proximity:
DVC Guests at monorail DVC resorts would be welcome to use the pools at other monorail resorts.
Same for DVC guests at Epcot DVC resorts.
Same for DVC guests at DS resorts (Saratoga and Key West).
Maybe other groupings work, but these are the ones that easily come to mind.
This would avoid the issues of people taking a midday park break at MK or Epcot and crowding the nearby resort pools. If someone at Bay Lake wants to use the Poly Pool, or vice versa, you're not adding to the overall monorail MK-break pool crowdedness.
DVC members staying at resorts outside of these groupings might feel excluded, but that's how it is. Not every resorts provide the same amenities. We would have to accept and deal with this just as we deal with all those other differences.