There was a question posted about this very issue recently from a hiker planning to resupply at the Portal. The announcement language seems to indicate that Inyo NF was allowing this resupply option, but is no longer doing so.

If they were charging all PCT hikers the $15 access fee, which was then given to Inyo, then Inyo NF just lost about $20,000/yr by this change. That special fee money would be legally required to benefit the Whitney Zone. Considering the low percentage of PCTA hikers that actually go down and back up the MMWT, this was probably a good deal for Inyo financially, while providing some flexibility for some hikers to resupply. I'm guessing there was an incident or incidents that precipitated this change. Or maybe there were just a lot more hikers using this option. Another impact of the "Wild" effect?