These are the only reasonably secure mobile devices with proper alternate OS support. It's not GrapheneOS forcing people to use these devices if they want a device to run it but rather other OEMs not providing what is required. The hardware requirements are listed at https://grapheneos.org/faq#future-devices. GrapheneOS has been working with a major Android OEM since June 2025 towards their future devices meeting these requirements and providing official GrapheneOS support.
> Their developers are constantly attacking GNU/Linux phones, which are the actual long-term solution for both freedom and security.
These devices provide objectively far less privacy and security at a hardware, firmware and software level. Linux itself is not a long term approach to privacy and security due to being a massive monolithic kernel written in C with very poor security. A long term approach will involve moving over current software onto a reasonably secure base. Moving to a dramatically less private and secure desktop operating system stack would be a huge regression in both the short and long term. It's not advancing as quickly in those areas, would not the usability/functionality people expect and is definitely not the future of secure devices. Android's current incarnation based around the Linux kernel is not the future of secure devices either, but it's far more private and secure today with a clearer path to moving forward.