Excellent point. I had a philosophy professor who let us know that it was neither his position nor purpose to indoctrinate us regarding the soundness of ideas. He very consistently stuck to his guns and gave every argument presented to the class the the best treatment he could, and no one ever figured out what position he took personally on any of them.

I asked if he did not consider the purely rational method he embodied a form of indoctrination itself. He smiled, and very considerately ceded the point that it might very well be the case and that if so, he was not aware of it.

All my other philosophy professors were folks who - for some reason - became angry when asked questions like that.