It's not a debate about what the IRS can do if they take the radical interpretation. The debate is whether it defeats the purpose and function of the IRS to take that interpretation? They won't get more money cracking down than they would if they encouraged legitimate users to pay taxes.

Same with WoW, they can crack down on it but doing that would not seem to be worth it politically or economically. It would hurt the economy and make the IRS look evil. The question is whether the IRS is willing to work with the community or are they intent on cracking down and from the John Doe summons to Coinbase it is looking bad but we don't know for sure.