A part of the criticism of Fairphone is exactly that they aren't even particularly sustainable or repairable, or ethical, have you read the posts. So there is no choice, not between the two groups you presented as opposing. They aren't even opposing each other as currently Pixels stand as fairly easy to repair and source some genuine parts for via Google's official iFixIt partnership.
An OEM reads the link above and gets the ball rolling as it should, privately, which was what Motorola did after showing up on the public Discord guild with an employee asking for further directions, but being aware of the linked resource already. Obviously GrapheneOS' merit is provably the product and the values it represents, not posts on social media (how could that make sense?). Think of that and how this one-sided criticism of "you should do that to avoid a certain image and get things done" of yours makes no sense either - it didn't scare anyone who would ever: currently only Motorola.
Edit: adding to the last point, the same applies to Fairphone but inversely, where they portray themselves as things they are not (sustainable, specially repairable, ethical, even privacy-respecting). Whereas a takeaway from your comment is that GrapheneOS is good but has a negative image (a false premise, in my opinion), Fairphone puts a lot of *effort* to construct a good image that signals the inverse of what they are. Effort ultimately signals intention.
Fairphone doesn't design or build smartphones themselves but rather their ODM partner does both. It isn't within their control to make devices meeting our requirements. When Fairphone moved to T2Mobile with the Fairphone 4, it came with significant changes to the hardware, firmware and software not within their control. They likely didn't want to remove the 3.5mm audio jack but the overall design of the devices isn't up to them. They want to portray themselves as being the ones designing the devices and stood behind it, but they likely didn't want it.
Fairphone has made it very clear they don't consider their awful updates and lack of important hardware-based security features to be a significant problem. Their response to our points has consistently been to downplay it. Fairphone has also consistently taken the approach of not responding to serious security issues such as several generations of their devices using publicly available private keys for signing firmware and/or the OS. Not acknowledging or addressing a security issue beyond partially fixing it for subsequent devices is worse than simply downplaying it.
/e/ and Murena spent years actively misleading people about GrapheneOS before we began regularly responding to it. They've taken the approach of misleading people into wrongly believing it isn't usable, isn't compatible with apps, somehow isn't a privacy project and much more. Their efforts have done immense harm to GrapheneOS, especially in Europe where they've mislead many companies and governments about it. /e/ and Murena have heavily pushed the false narrative of GrapheneOS not being usable by regular people but rather primarily useful to criminals and pedophiles. Those are their own words. These are 2 examples where they said it more broadly about hardened devices in general:
They've been doing this towards GrapheneOS specifically for years by misleading people about what it provides and wrongly painting it as an OS for criminals. Fairphone chose to become directly involved in this by responding to questions from the media based on a post with made about Murena with inaccurate claims. They chose to mislead people and to try to make it seem as if the accurate information we provided wasn't correct. Fairphone is not a bystander but rather explicitly sided with Murena in their attacks on GrapheneOS. Claiming highly private and secure devices are primarily benefiting criminals is outrageous and yet Fairphone backs the company repeatedly pushing this.
