Non-US dictatorships are doing this now. They use it as a tool to crack down on dissent. It's a patently terrible idea to criminalize something where it's impossible to prove intent.
When are we going to stop striving for some utopian perfection that is not there and instead realize/accept that most codified valuation have a conjugate trade off that can't be messaged away.
I know I'm not saying anything interesting here, but it bears repeating, there is probably no set of laws that (1) has strong protections put in place to resist abuse (2) is going to truly champion free speech and (3) still have real world protections against fake news that can't be easily circumvented.
What's the difference between a interest-group paid authoritatively-toned opinion-piece and fake news? How much of the former are you willing to nondiscriminatory censor to ensure squashing the later? What is the social/economic blow-black for that censorship?
Said another way, at what point does omitting facts become misrepresentation? And how many people's livelihoods are you willing to bet on the quality of your distinction?
When it comes to fake news, I'm as disgusted as the next person, but not every misuse of free speech deserves the special legislation that we grant to hate speech.
It's basically going to prove impossible to find a definition of 'fake news' that everyone is happy with. It can't just be 'Anything that some political group does not approve of' for instance, and it must be neither too broad (including all sorts of innocent publications, like tabloids mentioned earlier, foreign or historical propaganda, advertising that criticises its competitors, etc.) making it impossible to enforce, or narrow (fail to include certain categories of fakery) thus allowing loopholes and failing to accomplish anything.
But ... I think there are pretty good laws in place at the moment to deal with slander, libel, defamation and generally saying (or publishing) untrue things about people (or companies, entire groups of people defined by some shared attribute, locations, etc.) in a way that harms them (materially, or emotionally, maybe just potentially), and they actually deal with the situation where the intent is humour or parody. Too much of the time people have this knee-jerk reaction to X, something happening on the Internet, where they decide that the Internet-relatedness of this X makes it special (despite it being simply the age old problem of Y, but on the Internet) and demand a new crime of 'X' be created with incredibly harsh penalties like life in prison or death or billion dollar fines. But in general, it would suffice to continue to prosecute people for Y, just making sure that the Y-on-the-Internet cases also get looked at and prosecuted equally. I have no real problem with adding 'but on the Internet' as a qualifier to exiting crimes, in the same way as 'with a firearm' or 'while intoxicated' get tacked on as modifiers, increasing prison time and fines as appropriate, but this is almost never put forward as a suggestion.
So maybe we just need 'Libel, but on the Internet' to be prosecuted more often? Meh...