Character mistake: When Mary is in the execution chamber, about to be incinerated, there is a voice over of the countdown till her death. They count back from 9 seconds and say 8 seconds, 7 seconds, 6 seconds, etc. The count is too slow. Every time they say a second, it's actually two seconds having passed. (01:22:10)
Character mistake: The red ribbon with Mary's scent. Preston always holds it in his right hand and keeps it in his right pocket. However, Yurig (the leader of the Underground), during Preston's low detector test where the Resistance is ensuring that Person really has begun to feel human emotions, Yurig says: "you carry a ribbon with her scent in your left pocket. You smell it sometimes when you think no-one is watching...etc." But it was never in his left pocket, always in his right.
Chosen answer: As I see it, the point of the speeches is not to evoke emotions in the listeners, but rather to show what emotions such as anger and jealousy lead to in the course of human history. So they use historic "evidence" to justify their actions (such as killing sense offenders) and to show what emotions can lead to.
Andreas[DK]