I think you got the setup of that radio lab episode and not the later points. The points was that: a) plants are a lot cooler than you think b) looking at things from a non-standard position can lead to new insights even if that position might be wrong c) anthropomorphizing causes people to assign values to them that may or may not exist regardless of other evidence.

The turn was after hooking you on all of the feelings by anthropomorphizing the plants more to you, then went back to cold logical examination that there is no structure in the plant for pain or learning and literally pointed out the manipulation they did. Radiolab does this a lot, manipulates the listener to get you meta insight into yourself.