it does not matter who's faster. Only the Civic would be forced back if F150 was also fast. The energy needed to be absorbed is proportional to squre of relative speed, which is mostly taken by Civic. You can try your high school physics on this.
It's like someone hit your body with his fist, according to Newton, the forces on each other are the same, only difference is the fist can handle it better.
Think it this way, if Civic was sitting still while F150 was hitting it at 70 miles/hour, do you think Civic would just be fine?
Does that matter it's egg hit stone or stone hit egg?
The problem is Civic bumper was useless when it's hit by a higher F150.
When we bought our Pilot we were looking for a van with higher bumper, and that's the only thing available at that time to my knowledge.