You're only missing two from Enterprise: The Expanse and Home, in both cases characters discussing the MACOs and referring to them as "the military." So yeah, there are five references in all Star Trek saying Starfleet isn't military. It should also be noted that fourteen years go by in the real world between Peak Performance and The Expanse during which we see Starfleet fighting a war, so it's debateable how seriously the writers even took the line during those years. Even the Abrams movies at first tried to dance around the issue in Trek XI with the line about Starfleet being a "humanitarian peacekeeping armada" (which still sounds like a military) before flat out calling it non-military in the next two movies.Off the top of my head:
TNG: Peak Performance
Star Trek Into Darkness: By Scotty before he quits.
Star Trek Beyond: Scotty again, talking about Edison.
If we're just going to say "Starfleet isn't military because canon" how then do we avoid the simple fact that Starfleet officers are disciplined in a court martial? The term literally means "military court" and not only has it always been used throughout all Trek, it's the title of an episode.Because the people who made the show say that it isn't.
I swear to God, you cast an actor to play Kirk whose eyes aren't the same color as Shatner's and fans lose their shit because it contradicts something they call "canon" - but you take things said on the shows seriously and people want to dismiss them because they don't like them.
Besides, Starfleet only stopped being a military because Roddenberry wanted to try to discredit Harve Bennett and Nick Meyer. If the Great Bird can dismiss things simply because he doesn't like them, so can the fans.
IIRC, the novels do play with that. I can't remember which it was, but there was one where two aliens are conversing. One says something like "Starfleet isn't military" and the other responds "only they think so." Pocket Books does realize Starfleet is military, and while licensing agreements may require them to tow the party line, they do frequently work in little in-jokes as a way of winking to the fans and saying "we know, it is really is a military."From a strict in-universe view, somehow I always picture 23rd century Klingons and 24th century Romulans and Cardassians laughing their a….s off when they hear that Starfleet isn't military.