I do find it interesting how this opinion has taken root in Elite, because as you point out, in other games people don't complain. But what makes it "part of the game" in those and not Elite? When the game gives you full control over what level of player opposition you might see, why does this keep coming up?
You mention that those games "establish very early on" the stakes, and Elite could certainly do a better job of communicating the power gap between NPCs and players and how to deal with that. But I also wonder if giving that choice did somehow lead to the idea that being completely safe in Solo is the "true" game, and therefore Open is out of place for going against that. The game gives effectively no useful information on how to survive these encounters, yet there's a big button on the main menu that says "never get attacked again". I wonder if those other games would see similar effects if they also included a button to deny all player opposition.
I think, not "I know", this goes all the way back to the kickstarter where all of the "investors" wanted something different...and so to get the investment from the investors, many different play styles were catered to.
I say I think and not "I know" as I've only been around ED for 4 years, and a couple of weeks. I've read words to that effect in other threads on this forum.
Back in fall of 2015, I was looking for a new game, I narrowed it down to two choices. Elite Dangerous and Wasteland 2. Research told me that Elite dangerous had PvP, and I didn't want any part of that, it scared the hell out of me. I've, even to this day, never been a competitively skilled player in any game. Wasteland 2 was purchased.
In mid to late summer 2020, I was looking for a new game...I tried Solar 2, Warframe, Destiny 2, Drifter, Ravensword, Neverwinter, EVE and Everspace over the course of about 4 to 5 weeks, then I "broke down" and tried Elite Dangerous and I remembered playing both Elite on PC in the 80s and Frontier on Amiga in the 90s, and it fit like a glove, and then I got ganked, several times, in different locations (CGs, AXCZ, Deciat, etc...), and I almost quit, that was not fun...so I played in PG, mostly all by myself...
Fast forward to now, I play 99% in Open, I never fight against other players, except among friends, I play a very slow game of progression* and even I am starting to see the seeds of meaningful PvP in my future...someday...today I always run...and I almost always, > 85%, get away...but I also never risk anything when I go to "play with the gankers" either...so its still meaningless...and gets boring quickly...
* I have over 5500 hours of play time, I don't have all of the ships unlocked, I have not unlocked all of the engineers, I have not tried all of the mission types, I have only soloed a cyclops, I've done almost no Ody engineering, etc...