I agree it's foolish for fans to boo a pick just because they didn't anticipate it. But I believe that was one of the reasons for Packers fans booing Thompson for that pick. Before joining the Packers Harrell had right leg surgery, broke his ankle, re-injured ankle on first snap back, another ankle injury, and a biceps injury all causing him to miss about 30% of his college games. So yes, I think there is merit to the injury risk label. But the only thing I blame Harrell for is arriving at TC overweight and out of shape.
After the draft Thompson said they got offers to trade out of that spot and Jacksonville did trade out one pick after the Packers so we have an idea of what Thompson was offered. Jacksonville received Denver's first, third, and sixth rounders for pick 17. If they offered the Packers the same deal, Thompson would have only had to drop 5 spots in the first round to pick up an extra third and sixth pick, or better. So with perfect 20/20 hindsight...
I remember sitting on my couch during that draft and when they announced the pick I said "WHO?" grabbed my draft guide and saw they picked a projected 3rd to 5th rounder.