Edit January 19: FLI has made a substantive statement about this issue:
https://futureoflife.org/rejection_statement/
This seems concerning. It is claimed that the Future of Life Institute, run by MIT professor Max Tegmark, offered but did not pay out a grant to a Swedish far-right foundation. The character of this foundation and its associates is well-known in Sweden. Expo is an old and respected watchdog organization specialized on neo-nazism and related movements.
https://expo.se/2023/01/elon-musk-funded-nonprofit-run-mit-professor-offered-finance-swedish-pro-nazi-group
Is there and/or can you get independent verification of this? I understand the desire to not publicly reveal grantee/grantseeker details so I'm not necessarily saying you should make your emails to NDF public. However, it'd be helpful confirmation for an independent third party to verify that FLI did inform NDF of the rejection before the Expo.se inquiry, and/or some confirmation that the description of the FLI leadership decisions are roughly as you described them.