Actually, hardly any of what you described as "opinion" actually qualifies as opinion.
Opinion is a unique type of belief. It is unique in that it can never, under any circumstance, be proven true or false.
"Navy blue is better than scarlet red."
THAT is an opinion. You will never actually be able to say "the fact that OPINION was incorrect" because you'll never be able to prove it incorrect. We've lost sight of this, largely due to the ridiculous proliferation of post-modernist dogma. If you can prove that something is incorrect, then by definition, it cannot be opinion.
So let's take the murder thing. That, in reality, is an assertion, but it takes more than raw emotion and confirmation bias to establish it as a fact. It is dishonest to assert baseless speculation as though it were a matter of fact. You have to consider all the elements that deem any killing as a "murder," juxtapose it with what happened, and see if it matches. Derek Chauvin, for example, did murder George Floyd. That's not an opinion. The state more than satisfied its burden of proof beyond all reasonable doubt, which if you ask me more than qualifies for an establishment of actual fact. The same applies to the police shooting here. Was it justified? Again, take 1) all the circumstances present and juxtapose it with 2) how the law defines a justified shooting by an officer of the law. If the two fit, he's not a murderer. If the two don't fit, he's a murderer. Shouldn't be that hard.
What OnBoard did with the Georgia thing was neither fact nor opinion. He lied. Just straight up lied. Recall how this came about. He posted this:
"Is this the Ga. law saying you can give a bottled water to someone in line, but it can't have political candidates name or political party on the label ?"
There's no such Georgia law. It doesn't exist, but he asserted its existence as if it did. He asserted baseless speculation (i.e. something that's either not evidently true or evidently not true) as though it were a matter of fact when he knew full well it was not a matter of fact. Even if he actually believed it was true, as he stated in his immediate walkback later, he at least knew he couldn't prove it, as evident by his citing of a radio program as the source of such feeble nonsense. If he can't show it, he don't know it. But even with that confession, it's still dishonesty; not opinion. Radio programs don't work like a Norman Finkelstein book. Their statements aren't riddled with footnotes of citation, so it's not like they were literally citing anything when they said that. If anyone on that radio program actually did say that, they lied.
One of the other effects of post-modernist dogma is that we go out of our way to, relatively speaking at least, let rubes off the hook while still indicting the real liars. That's stupid because it blurs the line between the liars and the rubes, and the truth is that line is paper thin at best. If you're dumb enough to believe improbable claims from questionable sources on insufficient evidence, that just makes you a fool. But you're only a fool if you keep that shit to yourself. When you start spreading around those improbable claims to others and pretending as if you know they're facts, you're telling lies. Even if you walk them back later, you still told lies (just like a murderer is still a murderer even if he deeply regrets doing it and shows deep, genuine remorse and contrition to everyone for having done it), and you have an obligation to fess up to it and suffer the consequences. That, ladies and gentlemen, is what we like to call "personal responsibility."