I agree with you --- it is a support system. To remain supportive, a person has to refrain from curt phrases & employ diplomacy when driving home a point. To say "You're being naive" is inherently condescending, especially in writing with no emoticon. It never was about naivete, anyway -- it was about unfamiliarity. You're new to Apple devices, policies, and methodologies. I am, too.
I had this very issue last night. I would have asked the question about the "lock code" being given out -- that perhaps that indicated not stolen. But for all Apple knows the phone could have been stolen with the thief knowing the passcode -- or when they stole it perhaps it had no numeric passcode. But see, here I'm out of my league. I think the phone will make you choose a numeric code even if you use the fingerprint mode, but I'm not positive. And I cannot be positive, nor could you, that any answer on the thread is absolutely correct.
The Restore (through iTunes on a computer) option was one I tried. It failed. The phone still wanted the ID and password after I'd reset it and put fresh software back on it. See, that's because I'm FAMILIAR with that. I learned it. Why would anybody just take the word of one or two people and not try something someone suggests? Even if multiple people say the same thing, the lone dude who suggests a solution may be right and the others dead wrong. The seller's failure to respond is not necessarily an indication of the phone's being stolen -- but a very likely one.
Also, the comment "Just accept reality and move on" is not only rude, as well, but presumptuous. Why would you need to be commanded by someone to "move on" or "accept reality" when you do not know if what they're saying is true -- that's the presumption -- that anyone would simply take Kilt's answer as true, and wholly true, complete. Perhaps he's under some spell that causes him to think his Kilt makes him omniscient. I assure you, he's not. Ha.
The complete and true answer you got was that, in your situation, only Apple CAN do it, but ONLY if you have the original receipt and a valid ID to prove you're the original owner. That is something I deduced last night as I gave up my quest to get around the problem.
All this to say that you are right, Kilty Boy WAS A TAD HARSH. Please excuse my rambling -- but it's fun for me to just let it all hang out sometimes! --- Kinda like the Kilt guy. HA!
Diplomacy/Civility translation:
No offense, but I believe you're being a bit naive. It's probably best at this juncture for you to just accept that it's quite likely stolen, and you've been duped. That's my opinion. It happens to the smartest people. Then you can move on and get a phone that works! Good luck!