In a new 100-page document advising faithful on how to pursue holiness in the modern world, Francis said "defamation and slander can become commonplace and respect for the good name of others can be abandoned... even in Catholic media".
The pontiff wrote: "The result is a dangerous dichotomy, since things can be said there that would be unacceptable in public discourse, and people look to compensate for their own discontent by lashing out at others.
"It is striking that at times, in claiming to uphold the other commandments, they completely ignore the eighth, which forbids bearing false witness or lying, and ruthlessly vilify others."
In his third Apostolic Exhortation, called Gaudete et Exsultate, Pope Francis also suggested that believers ought to care for the welfare of migrants as much as they are concerned about preventing abortion.
He went on to say: "We often hear it said that, with respect to relativism and the flaws of our present world, the situation of migrants, for example, is a lesser issue.
"Some Catholics consider it a secondary issue compared to the grave bioethical questions.
"That a politician looking for votes might say such a thing is understandable, but not a Christian, for whom the only proper attitude is to stand in the shoes of those brothers and sisters of ours who risk their lives to offer a future to their children.
"Can we not realize that this is exactly what Jesus demands of us, when he tells us that in welcoming the stranger we welcome him (Matthew 25:35)."
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