Some contributors are pseudonymous. The choice for a developer or mod to be is on them. You can't really reverse what you put online about yourself. I can't just disappear and "go anon", and especially not hide at a nation state level. GrapheneOS has been around over a decade and has public founders and people involved for an extremely long time... I had been around since previous namings.
Because of the nature of things like a non-profit foundation, there has to be incorporated directors registered with authorities. Being a mod you wouldn't get much disruption from me if I just had to decide to pack things up.
This isn't all bad as we have a position of trust and accountability, unlike proprietary mobile 'security' projects ran by unknown individuals that get seized by LE for ACTUALLY enabling or being involved in crimes i.e. EncroChat. Seeing what we're up to is helpful.