"PhotoShop" has become a derogatory term of the ignorant masses, based upon cutting and pasting images that weren't a part of the original scene, but I would expect a "professor" to understand this and realize that PP in general is an important and integregal part of all digital photography.
Nearly all my shooting is for magazines and newspapers, where such antics are not only frowned upon, it can end your association. But I use PhotoShop and similar softwares to enhance every photo before sending it out. I consider it unprofessional not to do so. I do, however, avoid layers, blending, HDR etc., because although not unethical, I suspect publications have software programs that flag such things.
At any rate, I would think that any course that didn't include considerable attention to PP techniques to be a disservice to students.