Anathematizing a person isn't the same thing as condemning a person to hell. Rather it is a form of excommunication (prohibition from receiving communion). The ultimate fate of the person in question is understood to be in God's hands.
To answer my own question, yes, it's a modern thing. Here's the original ritual of anathematizing:
"Wherefore in the name of God the All-powerful, Father, Son, and Holy Ghost, of Blessed Peter, Prince of the Apostles, and of all the saints, in virtue of the power which has been given us of binding and loosing in Heaven and on earth, we deprive (Name) himself and all his accomplices and all his abettors of the Communion of the Body and Blood of Our Lord, we separate him from the society of all Christians, we exclude him from the bosom of our Holy Mother the Church in Heaven and on earth, we declare him excommunicated and anathematized and we judge him condemned to eternal fire with Satan and his angels and all the reprobate, so long as he will not burst the fetters of the demon, do penance and satisfy the Church; we deliver him to Satan to mortify his body, that his soul may be saved on the day of judgment."
Looks like this was changed to exclude the hell bit in 1917.
That quotation doesn't say exactly what you seem to be suggesting. After all, it specifically includes the hope "that his soul may be saved on the day of judgment."
Well, in Catholic theology that's the only thing that being condemned to hell can mean. :-)
Admittedly, the wording is very confusing for those not familiar with Catholic theology, but this quotation basically means "If X continues on his present course, he is in danger of damnation. We withdraw the Church's spiritual protection in this life in the hope that he will repent and be saved from damnation."
