You missed the point those 6 to 17 percent are just regular people. They don’t shoot fire from their hands.
Remember even a level two adventure is a very very small percentage of the world’s population. Most people are way weaker in DND. Being a level 2 adventurer is way beyond a year of BJJ
I don’t know man I can cast fire from my hands. That’s pretty over powered. Plus Steve over there can channel divine energy into their weapon. I think we can take a giant. It’s just like a really big human right? And there’s 4 of us.
That’s not an unreasonable viewpoint for inexperienced adventurers.
Now if your character is a little more familiar with monsters and other adventures they would know better.
To your Orca example I’m just a guy. I have no abilities. A commoner wouldn’t try to fight a giant. Now if you give me the ability to shoot lighting from my hands and 3 other people with similar abilities, I could reasonably believe I could fight an Orca.
Friendly reminder that 6% of Americans think they can beat a grizzly bear in a fight. A shocking 17% think they could beat a chimpanzee. These are just regular people without special skills.
https://www.newsweek.com/surprising-americans-beat-wild-animals-fight-experts-1691793
To be fair if you don’t make it clear to the party that they can’t take the creature or some other kind of warning there’s no way for them to know if they can handle it without metagaming.
I the player know a level 2 can’t take on a giant, but does my character know that
Let’s say as a party you’ve taken down a few monsters already. Without knowing the proportional strength of a chimera to the monsters you’ve already faced how would you know?
Like let’s say I did kill an Orca on my own. Then I see a polar bear, the Orca was a lot bigger so seems reasonable.
Now living in the age of technology, not a fantasy setting, I personally know that a polar bear would be a lot harder to beat. But how’s an adventurer supposed to know that? They don’t have wikipedia and national geographic in most fantasy settings. It’s not unreasonable to believe when encountering a creature that no one in the party is familiar with it at all.