In what is essentially an un-moderated, certainly uncensored, forum removing the lock ability ensures it stays that way.
There is no doubt he is a spammer, technically illegal - I can point you to probably a dozen if not more websites where he consistently just spams (not just the main poster forums). So by locking out his posts he removes the rights of others to post their thoughts, that is censorship - or are we now going down that road?
He doesn't care, he adds no value to this forum in any discussion, personally I'd rather see him removed simply because of his spamming but I understand and accept the reasons for not doing so (even if in this case I don't necessarily agree with it )therefore his posts should be 'unlocked' so it remains an equal forum for all.
A simple option Admin can attend to.