 Raymond comments, " ' Ninian was a ninny to locate in a mercantile suburb where any little thing out of the will cause talk.  How thankful I am that our era has completely disposed of the mercantiles --' "

What irony can be found in this statement?
"He's dissatisfied with the current social order and killing you is part of an elaborate plan he's formulated to change it. And, on those worlds, it's far cheaper to use native labor than to ship out all that expensive machinery. In that way, there would be no space-drive, and, hence, the Terrestrials would never get to the other planets and oppress the local aborigines. Of course Ninian was a ninny to locate in a mercantile suburb where any little thing out of the way will cause talk. But Raymond rushed on: "Soon as Ninian goes and I'm in full charge, we'll get a more isolated place and run it on a far grander scale.
 Rather than be grateful that gossip has been eradicated in the future, Raymond is thankful that an entire class of people has been eliminated.
 It truly is sad that someone who had the insight to create a plan as detailed could not have avoided living in such an area.  He calls the master behind their grand plan "a ninny."  Raymond has no right to call anyone "a ninny," as he is the dumbest descendant to arrive from the future.  Rather than be grateful that gossip has been eradicated in the future, Raymond is thankful that an entire class of people has been eliminated.