Why should we be ashamed of polygamy?

When Gordon B. Hinckley is asked by the media about polygamy, he often doesn't give an answer other than saying 'it's all behind us now'. This sounds like he is implying that maybe it was a mistake but we don't do it anymore. He doesn't defend the practice or say that it wasn't wrong. He wants the LDS Church to appear mainstream instead of taking the opportunity to explain our unique and special beliefs. He downplays it saying it was practiced by only 2-5% of the population vs the 20-30% that LDS historians say practiced it. Why doesn't he say that it was God's will, it was suspended for a time as it was no longer practical to be practiced, but will be practiced again in the next life and during the millennium when Christ reigns on the earth?

Are we ashamed of doing what God commanded us to do? Instead we make up excuses for it like we are ashamed of it. If it was right and true then, why don't we be proud of the fact that our ancestors practiced something very difficult in the face of enormous opposition?