Is it true that passive 3D projectors would require some special screen?
If so why?
I definitely hate active 3D glasses.
Yes, virtually all single beam projectors are active. This is because passive polarization relies on pixel perfect alignment of the light to the polarization material (screen medium). Active 3D however does not have that limitation as the glasses do not need polarization. There are costly dual projection setups which can be used passively, but they are also difficult to align and maintain. I prefer passive as well, but owning both types, I can say that active 3D has made advancements in the home. I prefer DLP 3D projector glasses even to those sold for Samsung 3D TVs now.