I can't believe what I just read.

There are no moral facts.

That doesn't mean that some opinions are more well-founded than others, or that some opinions are near universal, but widespread belief and/or agreement does not make something a fact.

Unknown facts are a different matter. These are things that can be demonstrated to be true, but are not yet known.

Me: “I believe that George Washington was the first president. Is that a fact or an opinion?”

Him: “It’s a fact.”

Me: “But I believe it, and you said that what someone believes is an opinion.”

Him: “Yeah, but it’s true.”

Me: “So it’s both a fact and an opinion?”

The blank stare on his face said it all.

Yes. It is. There's nothing strange there. The caveat is that whether or not George Washington was the first president is not dependent upon his opinion on the matter.

Opinions can be very important. They can be more important than facts. But, they are not provable.

EDIT: I'd add that facts are what lead to opinions. Opinions may be well-founded or not. Also facts can be wrong, or given inappropriate significance for a number of reasons.