Kurtz:
A concerned passenger may raise his concern, not push it even after it has been noted. When it crosses this line, he becomes a danger to the airplane. As to how much of a potential threat that 'concern' may actually be is not the passenger's call to make - it's yours, yes the one with all the bars, unless you didn't know that Kurtz? Why? Because you're the one who's supposedly got all the training, experience & facts at hand. Is this not so?
MM:
Kegworth/KAL may not have happened if someone raised concern. Communications. Agreed. Raised, not pushed. I trust you know the difference between the two (and by the way, in the case of the Iranian route, that pax was told to shut up because he was creating havoc in the cabin amongst other passengers as well which in the opinion of the cabin crew was threatening to turn ugly in spite of having been told that this was normal. You were not there, i was).
Back to the issue of the j/s - if the airline has an SOP or the country concerned has mandated a flight deck entry policy, then it is abided by. In this case, it appears that there was none, which made it the Capt's call - not the pax or even the SVP. Do you dispute this?
"The pilot-in-command is DIRECTLY RESPONSIBLE for, and the FINAL AUTHORITY as to, the operation of the airplane." - definition
For the most part, thankfully, passengers are not this obstinate/self-opinionated.