The Orthodox Info article will hopefully answer some questions.
The Orthodox Info article (which I read awhile ago) probably answers some questions with questionable or uncharitable answers. As Chris stated earlier, there is no "re-baptism" nor "re-marriage" - either they did or didn't happen. But sacramentally, the Orthodox Church doesn't recognize "sacraments" outside the church because all sacraments are tied to the Eucharist - and therefore, since the other "churches" are not connected via Eucharist to us, they aren't performing "sacraments" in our eyes. Now, if someone comes to the Church and had, say, an RC baptism, it is the Church's right to say that the Form of their baptism was good, and the Chrismation that they will receive when becoming Orthodox will complete the baptism as well... Or if the Church (through its unifying agent, the Bishop) decides that the Baptism and Confirmation of the RC were both good in form, then the prayer that He would read over the convert would complete them both (as he would invoke the Spirit to do so).
I don't know why we 'need' to recognize sacraments of those outside the Church or not - they're not in the Church, so it isn't our problem. We love them, and preach the gospel of love, but calling them fornicators or heretics is pointless --> since they're not in the Church we can't prescribe them epitimia
or corrective measures. If they stay outside the Church, then God bless them, and I hope He brings them to eternal life... But until then they're outside of The Vessel which sails to salvation.