("Guilty" may be the wrong word, because it's not a criminal offense, but I'm not sure what the right one is here.)
Defamation is a crime in many jurisdictions, including the US (not federally, but in over 20 states). Prosecutions and convictions are rare-but not non-existent. At least in the US, punishments are light (Wikipedia cites a study saying that the average custodial sentence for criminal libel in the US is just under six months). In free countries, prosecutions are generally reserved for particularly egregious cases (e.g. suppose A does some trivial thing to offend B, so as payback B plasters posters all over town accusing A of sex crimes, with the allegation being completely invented). Given this, the vast majority of defamation cases are civil not criminal.
I'm encouraged in seeing the turnout of Alex Jones ordeal and am anxiously waiting to see how Dominion vs Fox News unfolds. I am hoping that the aftermath of all this is that journalists/people-pretending-to-be-journalists/anyone-with-a-sizable-platform will be more careful about their reporting and statements. Of course this is all a murky area because many times it's hard to decide what is true and even harder to decide who gets to do the deciding but for getting the obvious things wrong and when signs of bad faith are clearly there the hammer should get dropped more often, I think such an environment would reduce chaos and extremism that we are seeing more and more of.