The article mentions several times how criminal naivete over the untraceability of Bitcoin aided the investigation - so why let the cat out of the bag now? It might be just that the IRS thinks it is not getting enough respect, but another theory is that Bitcoin is becoming known as being traceable, alternatives like Monero are currently effective, and the hope is to spread FUD by association and the implicit threat of future retroactive traceability.

To be clear, if that is the case, I have no objection.