“But It’s Just My Opinion…”
There are those who ask you about something in your field, you give them a response, then they proceed, at length, to give full airing of their view of the topic which is largely contradictory to yours and explain (usually with faulty reasoning) why the prevailing view is rubbish. They will then (out of some sense of humility, I’m sure) sign off with “but, that’s just my opinion.”
If you are graciously generous, you may take another stab at correcting their ignorance, at which point they shift slightly their arguments but come to the same conclusion, with the same ’disarming’ signoff.
I suggest you let them enjoy their opinion in peace. They obviously find more solace in their self-constructed ignorance than in refining it with expertise.