Whether BCX publishes the known spenders of rings or not is irrelevant, because it can be calculated by anyone at any time in the future.
He (or anyone) can't publish known spenders because of stealth addresses. All addresses on the blockchain are one-time-use, so there is nothing on the blockchain to link your transactions with each other so as to create a virtual "identity." In effect this is a potential compromise to "untracability" in cryptonote, which would allow some transactions to link with with each other, but not "unlinkability".
How successful that is depends a lot on how probable these linkages are to be made, which we don't know. It also remains to be seen feasible the algorithm is to perform, and what steps can be used to control the impact. We don't know any of these yet.
In any case it is interesting work that will help improve the technology (all cryptonotes) going forward. Anonymint deserves credit for coming up with it.