Just for the record, I’m not a ATMB or IMHO mod, so this is reflecting my viewpoints mostly as a poster and follower of board culture.
I tend to think that Kanicbird is caught in the grip of how the OP was framed. The OP mentioned near-addictive nature of their obsession with porn: “Honestly I was a porn fiend.” and then went on to explicitly ask the following:
Do you believe in demons?
Taking those in turn, we long have a board culture of advising those with addictions to see medical/psychological advice, sometimes given our natures in a slightly snarky nature, but normally from a place of at least casual concern.
For the second section, which not framed as a debate, it is opening the door too one. By my read, kanicbird shared theirs, which is their right, but that (likely unintentionally from the comments here) opens them up the same sort of possible debate the OP has.
The second point is more about general board culture. We tend to want verifiable, repeatable evidence. The number of times where a poster has said “the plural of anecdote is not data” is beyond the point of casual counting! Between that, and the near-universal love of Occam’s Razor, suggesting seeking medical advice is nearly a given.
That said, I personally would be uncomfortable (as a non-medical professional) of jumping to a straight diagnosis. It shouldn’t be insulting to need help with physical or mental issue, but all-to-often it is in USAian culture. I don’t believe any of the posters responding were intentionally using it as such, though there may have been a minor feeling of “this is the obvious first step, not asking a bunch of internet randos!”.
What I was really impressed with was @GIGObuster’s anecdote about his experiences, how easily it could be terrifying, but the resolution to identify and verify the problem without dismissing the very real concerns of the person having the problem regardless of the source.
So, TLDR: the OP directly or tacticly invited discussion of such beliefs. Given the board’s nature, we are aggressive on fighting perceived ignorance. Lastly, the response of suggesting medical or mental treatment isn’t wrong, but IMHO (!) the perceived insult was from a lack of tact - i.e. not a direct insult.