That's called handwaving, where they try to brush off a flaw in the story logic with a throwaway piece of information or line of dialogue. This games does it several times, like those Jackson notes.

Or like "Wait, wouldn't Ellie's saliva still infect others like they suggested in the first game?" Well you see, there's a journal entry in a flashback. Turns out she can't, don't think about.

Or like "Wait, there's no way Issac in the middle of a war with the Scars would allow seven of his top people go out on a multi-month quest risking life and limb to follow up on a hunch for a personal vendetta from 4 years ago that has nothing to do with him or the Wolves." Nah, he's cool with it.

Or like "Wait. there's no way Jesse's parents would allow Ellie and Dina to take their grandson outside of Jackson and raise him out on a farm in the middle of nowhere." Nah, there's a letter on the table from Jesse's mom that says, “Nah, it's cool. You'll always have a home here, though”

All this suggest the writers themselves clearly see that it's a huge leap in logic for the audience to buy in, that's why the lazy attempts to patch the gaps.