Was it right for Lot to offer his daughters to be raped?
I don't think Lot offering his virgin daughters to be raped (Gen. 19) was anything to be celebrated, despite his motivation to protect his visitors, do you?
No. Lot offered his daughters to the Sodomites in order to protect his guests. In doing so, he was choosing to commit one evil in order to avoid another; the Church clearly teaches that this is wrong: "One may never do evil so that good may result from it" (CCC 1789).
The Catholic Encyclopedia article on Lot explains: "Lot interceded in behalf of his guests in accordance with his duties as host, which are most sacred in the East, but made the mistake of placing them above his duties as a father by offering his two daughters to the wicked designs of the Sodomites." A Catholic Commentary on Holy Scripture agrees: "Lot cannot be praised. He chose what he considered the less of two evils" (195).