Was it really that big a deal to the membership?
Maybe I have tunnel vision, but how many DVC members actually pool hopped, we never did even when it was allowed, but I don’t visit during the summer when pools are likely to be jammed. As a member I’d far prefer to have a less crowded pool where I’m staying than a pool hopping perk I never used

.
I think my first visit to WDW they allowed any resort guest to hop, but there were far fewer resorts then. By the time of my second visit cash resort guest pool hopping was no longer allowed.
I don’t think it’s masses of DVC members crashing pools that are a big problem, I think it’s non resort guests of all types crashing certain pools & now that all of the pools are fenced they can more easily control access so they’ve decided to do something about the situation & the easiest something for CMs to enforce is to limit pool usage to guests staying at the resort.
Carving out an exception for DVC members currently staying on points at another WDW DVC resort is likely just too hard to verify for the CM handing out wrist bands & by leaving one exception they’ve left open the floodgates & SM ‘influencers’ will coach their followers to ‘just tell the CM you’re DVC’ if you want to take a break from the parks & swim at a nearby resort pool.