I can imagine this $58 fee is scaring off real users who use Tor to protect their privacy. But even if one of them pays the fee, it opens the gates for spammers to register accounts from the same IPs again. (correct me if I'm wrong here)
I think if one paid the fee, it doesn't reset the evil unit on that IP to zero
the evil unit only automatically decreases slowly in time by system
but it seems that many users login their accounts via that tor to post spam
so the evil unit keeps accumulating and never had a chance to decrease to zero
btw if it is high enough for a copper membership, the new user automatically gets it too
and if there is a new membership or perk introduced by the forum, the fee paid counts towards it