[thaumasiotes]

If you're going to account for deadweight loss, a tax break can be profitable while lowering tax revenue. Then it would be a tragedy of the commons from the perspective of those looking to maximize tax revenue, but good policy from the perspective of those looking to have nicer lives.

Ordinarily, the Laffer curve is just talking about tax breaks that raise total tax revenue, not tax breaks that bring a net benefit in reduced deadweight loss.