The only reason to believe that hiring more female economists is bad is because you think that, somehow, economics produced by female economists is inherently inferior to that produced by male economists. And that, my friends, is the very definition of sexism.Is that sexism? Let's compare the bodies of work.
Don't bother with the trouble of comparing work.
Sexism is not some evil force that we have to suppress at all costs. It is a biologically and socially ingrained tendency with significant reason to exist - namely that most women are not competitive intellects. The Marie Curies are rare and come around once every few centuries. Men always outperform women at the top end of the intellectual spectrum.