I have heard that that too, but i have to say that it is not only a pente thing. Rejoicing about people in hell has been almost always part of Christian tradition. Below are few famous quotes.

The sight of hell torments will exalt the happiness of the saints forever. . .Can the believing father in Heaven be happy with his unbelieving children in Hell. . . I tell you, yea! Such will be his sense of justice that it will increase rather than diminish his bliss. (Jonathan Edwards)

In order that the happiness of the saints may be more delightful to them and that they may render more copious thanks to God for it, they are allowed to see perfectly the sufferings of the damned. . .So that they may be urged the more to praise God. . .The saints in heaven know distinctly all that happens. . .to the damned. (Thomas Aquinas)