We could start a debate about the immorality of a religion that allows one to receive organ donations, but which does not allow its adherents to reciprocate. We could discuss how this selfishness is perceived by the medical establishment, or by the world at large. We could ponder whether it's ethical for Jews to prevent saving a life (or restoring the eyesight for someone who would otherwise remain blind) for the sake of the elusive concept of avoiding bizayon hameis. We could argue about the halakhic issues involving brain death. We could consider whether a frum Jew is religiously required to keep his/her dead carcass intact so that it will be whole when and ifTechiyas Hameisim occurs. We could discuss why donating/accepting a kidney from a living person is a mitzvah, but donating one from a dead one is perceived by some to be halakhically problematic. In fact, feel free to debate all of these issues, if you so desire.
But that isn't the purpose of this post. The sole purpose of this post is to make it as widely known as possible that having an organ donor card is not contrary to halakhah.
All of these well respected rabbis do.