I get your point. However, don't falsely shout fire in a crowded theatre for the risk of patrons getting crushed in the stampede.
Having differing opinions is proper and right in a free and democratic society. And provided these are based in credible arguments and facts.
The problem is a-holes who come out with cranky beliefs, misinformation, conspiracy theories, etc., You could ask 'well what's wrong with that?'. Some of it could be harmless such as believing in fairies and flat earth. But unfortunately some of it isn't, such as:
The moon landings never happened. Nutters then hound Buzz Aldrin
Man punched by Buzz Aldrin STILL says moon landing was fake
MMR vaccines are bad. Count the cost later when your kids are affected.
The victims of the Sandy Hook shootings are fake and their parents are then hounded by CTers calling crises actors.
FACT CHECK: Crisis Actors Uncovered?
Pizzagate leading to one nutter turning up with a gun to do 'research' into the non-existent child abuse ring.
5G will cause people to die so burn down the towers.
No-one died on 9/11. All the victims were fake and the crises actors were later bumped off/now living anonymously with fake identities. Take your pick.
The helicopter crash in Glasgow never happened.
Lee Rigby didn't die/was a crises actor/was a CGI/it's a plot to pit raise fear in the public and therefore control.
There's loads more of that sort of crap.
So it's important to counter false narratives where there's a major risk to safety and security. As well as stopping people just being effin idiots, as a for instance belief in flat earth apparently increased a few years ago, the culprit being the internet. Harmless? Maybe. But not for some.