Members must have some privilages that guests do not have or it's not much point in registering..
Yes you already have; post and talk ability, pm other members, also you can invite people too. Those privileges have not given to guests. So you still have reason to register. But I must tell you; registering is not a rank, it is grant. To share. You are registering to share, not hiding, nor kicking outsiders. That 127/21 ratio gives you huge people to show your experience.
I offered attachment solution as a cover of link deletions. Its overkill if you block whole people not to see links.