The concern with winlink is twofold:

1) It transmits without checking if the frequency is already in use, and is thus a source of interference to other users

2) It uses a proprietary protocol that requires purchasing expensive hardware froma single company (https://www.p4dragon.com/download/SCS_Pricelist_2019_REV-A.p...) to decode

The solutions proposed are

1) Limit "Automatically Controlled Data Stations" like Winlink to a specific range of frequencies 2) Limit the protocols they use to ones that "can be be monitored, in it’s entirety, by 3rd parties, with freely available open source software"

You can read the petition at https://ecfsapi.fcc.gov/file/100918881206/PETITION%20FOR%20R... for more details.