Who the OP is does affect the prior probability that he is wrong. If the majority of economics viewpoints held by non-economists is wrong (which is a big if), then the commentators would be justified in assigning near-zero amount of credence in what he's saying. If the OP presented a detailed, technical argument in favor of his positions, then this would "screen out" OP's level of experience. But barring such an argument, the commentators may have a point.
That being said, the average internet commentator may not be the best conversation partner.
Especially in the comments of political articles or about economic issues I find myself arguing with people who question my authority about a topic rather than refute my arguments.
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Examples may be:
1:
Me: I think money printing by the Fed will cause inflation if they continue like this.
Random commenter: Are you an economist?
Me: I am not, but it's not relevant.
Random commenter: Ok, so you are clueless.
2:
Me: The current strategy to fight terror is not working because ISIS is growing.
Random commenter: What would you do to stop terrorism?
Me: I have an idea of what I would do, but it's not relevant because I'm not an expert, but do you think the current strategy is working?
Random commenter: So you don't know what you are talking about.
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It is not about my opinions above, or even if I am right or not, I would gladly change my opinion after a debate, but I think that I am being disqualified unfairly.
If I am right, how should I answer or continue these conversations?