After Raji left and Guion was busted in the WeedCash Estate Wagon, it was clear they needed D line help. If Clark was the highest rated player on the board, I am sure they were happy. But highest or not, when he got a first round grade from the team, GB was taking him.
Sherrod might have been the last Tackle with a first round grade (by some services) but he was not a lock to get picked at the end of Round 1. Packers had a definite need at tackle as Chad Clifton was old, Tauscher was out and Bulaga was needed at RT.
Thompson has not stuck simply to BPA at other times as well. I think BPA is his preference, but he obviously considers need at times. Even early.