The most frequently cited sins in Jewish tradition are sins of speech. Some are direct, such as gossiping or slander. Others are indirect, such as embarrassing someone in public, which is usually a consequence of saying something callous or unkind.
As a result, shemirat halashon, guarding one’s tongue, is a powerful value in Judaism. In part this is because we recognize the potency of words. If I tell you something discreditable about another person, even if it is later disproved, I cannot force you to forget and the faint whiff of scandal sticks to their reputation, even if wholly undeserved. One of our greatest sages, the Chofetz Chaim, devoted much of his life to exploring and explaining the ins and outs of proper speech.
Why is it so hard to avoid negative speech? Because it so powerful. “He is a nice guy” does not have the punch of “He is a jerk.” But Jewish tradition reminds us that loose, cruel speech is wrong, whether done privately or publicly. I hope all around dinner tables in the Jewish world parents are explaining that whatever their political position, our sages are unanimous on the importance of dignified speech, and the destructive power of the tongue set free.