I don't think anything is irrational or unreasonable when it comes to this kind of situation. Even putting aside the distraction issues over the summer, the way people who fundamentally do not understand the process blithely make comments about how someone has obviously got a place or whatever is extremely annoying. I'm assuming your DD has said she "passed" and the neighbour has taken that to mean everything is fine, not knowing how the system works at all.
FWIW I still haven't forgiven one of the kids' grandparents for her eve-of-results message saying she'd bought DS a present as a reward for passing, and when I replied that he hadn't yet she sent some cheery emojis and something about knowing he obviously had because he's so clever.
I've also spent a couple of months avoiding an NCT friend whose DD passed the Bucks 11+ who keeps doing the "oh well, it just shows that a grammar isn't the right place for your DS but he'll do well wherever he goes" bullshit.