It's not that it's reported in Box 7. It's that working interests are by definition subject to SE tax, exactly as a general partnership interest would be. (And a working interest is basically equivalent to a GP interest in the well.)

There's a really old court case where a little old lady who inherited her interest was found to be not subject to SE tax. But if you're going to take the position that it's not a ToB for SE tax, it's hard to also be arguing that it's a ToB for QBI.