Maxperson
Morkus from Orkus
But, it doesn't say they don't need to roll. It flat out states that they don't need stats AT ALL. It doesn't need to say you don't need to roll because, in 5e, you never need to roll. And, just like all your examples, since you don't need it, not having it doesn't really matter.
Dude. "You don't need to roll ability scores for the NPC..." is quite literally the first line of the Abilities section on page 89.
Now, to be fair, I get what you're saying. Like I said earlier, this is just a sidebar of the whole "rules as physics" debate, which will never be resolved. It's a personal style issue. For me, that fisherman catches fish every day, not because of anything to do with the game mechanics, but, because I'm the all powerful author of the setting and what I say goes. Did that fisherman catch a really big fish today? Yup, he did. Jumped right into his boat. Didn't even need to use a net. How do I know that? Because, as the DM, I get to do that.
Right. I'm not saying you have to know what the ability scores are and can just dictate things, but it's a fact that every NPC has them. If they didn't, they would be dead.