From:
https://lawyerofgames.com/insights-into-why-hyperbola-gnu-linux-is-turning-into-hyperbola-bsd/
Another of the reasons is that the Linux kernel is no longer getting proper hardening. Grsecurity stopped offering public patches several years ago, and we depended on that for our system\u2019s security. Although we could use their patches still for a very expensive subscription, the subscription would be terminated if we chose to make those patches public.
Such restrictions goes against the FSDG principles that require us to provide full source code, deblobbed, and unrestricted, to our users.