Q&A: Galaxies, Galaxy Clusters, AGN, and Quasars
The theoretical understanding of the formation of jets still has a long way
to go in explaining how jets can have such tight collimation. But, the answer
likely has to do with magnetic fields and the rapid spin of material as it
gets close to the black hole. From symmetry, it's not surprising that
they're directly opposite each other.
Many observations of jets are made at oblique angles and don't require us
to be looking down the barrel, so to speak. See this Chandra work on M87,