Sorry, but you're wrong.
The foam possesses a low relative density, therefore having a very high surface area compared to weight. The laminar boundary layer- the "layer" of air right on the skin of the tank, which tends to move slowly, is a very thin layer- in this case, with the speeds we're discussing (~1,900 MPH was the last NASA estimate I heard about Shuttle speed at time of foam separation), it was probably a few molecules thick. So, as soon as the insulation broke loose, it was immediately decelerating. Considering the high surface area to mass ratio, the delta-V would have been very high... Imagine following a garbage truck driving down the highway at 60MPH, and a piece of styrofoam flies up out of the front of the garbage bin... By the time It's a few feet above the truck (and out of the turbulent air from the truck) it's ground speed is zero. I've watched this, before... What you see from the side, is that the foam pops straight up, is stopped in place by the wind, and the truck rolls out from under the foam...
At 1,900 MPH, and a distance of what... 50-75 feet???
Oh, yeah, there was a significant difference in speeds, by the time the foam hit the wing...
If the foam happened to be relatively hard, then regardless of whether it was a direct blow or a glancing blow, it is likely that tile damage would result...
CE
This would be funny if you weren't serious. It would be interesting to know what speed you call "significant". Say the difference in speed between the shuttle and the foam were 200 miles per hour. That calculates to 293 feet per second. So it makes the 50 foot trip from break off point to the shuttle in 1/6th of a second. Is that what the video showed?