Here we go, they contradict themselves later: "Computational general equilibrium (CGE) models provide an example of accepted computerized problem solving in economics."
I don't see this as a contradiction. The authors probably would include simulation and computerized solvers as "computerized problem solving". Such applied techniques are certainly welcomed in the field of economics. That said, they are not usually considered a theoretical approach. So, using them in a paper won't get you published if a journal is looking for a theoretical advance.