If "knowingly spreading misleading information" was illegal, we wouldn't have any of these problems.
It should be a computer crime to engage in the most egregious of these offenses.
In the case of electoral campaigns, it should be covered under Sedition laws.
In the United States, libel and slander law has always been based on truth and intent. If a person makes true statements about a person, it doesn't matter how much damage it does. There is no crime. If a person makes false statements about a person, it has to be done with malicious intent, for it to be a crime. If the speaker believes his statement to be a fact, as determined by the court, again no crime.
Then it gets really complicated. If the speaker does not believe anyone will take the statement as fact, it doesn't matter what he says. Larry Flint can publish a parody Whisky advertisement in which Jerry Falwell tells of losing his virginity to his mother in and outhouse, and there's nothing Jerry can do about it. I've seen it done.
Sedition is a tricky matter. Sedition is the act of talking bad about the government.
I'm not sure we have sedition laws in the US. They tried it once, but it didn't work out. There are plenty of laws which deal with conspiracy to commit a crime, so if someone makes plans to blow up the Capitol, we have that covered. However, if someone says, "They ought to blow up the Capitol," that's okay.
Lying is only a crime in special circumstances. If all lying were prosecuted, we wouldn't have time for anything else.