Is this related to Stallman going back to the FSF?
Different companies would choose which list to use according to their own politics and culture.
Totally hypothetical: Coinbase and Google will probably turn rms-open-letter into a denylist. Twitter will do the opposite.
This is all conjecture, but I could see it happening. It's why I feel I shouldn't sign.
The other is full of throwaway and inactive github accounts.
(FWIW I haven't signed either, and don't know enough about RMS' actions to commit to a perspective).
Edit: it seems some people are not interested in this data