If nobody else is allowed to distribute leaflets then the decision seems fine.
If Christians were singled out then this is just discrimination.
I would find it irritating and bothersome to have a leaflet shoved in my face but there are worst things in the world. I celebrate people's rights to free speech as long as it does not impige on mine.
If Atheists, Buddhists, Fairy worshippers, Nudists or Trekkies have the same rights then so be it.
I do wonder though whether Christians would be thrilled to have Atheists doorstepping them each Sunday on their way out of Church with leaflets, speeches and public demonstrations... I suspect this would not go down too well.
I have never had anyone apart from Christians and Hare Khrishna trying to spread their creed to me.