[StanislavPetrov]

>The existence of a consensus opinion isn’t an argument from authority.

That's exactly what it is. The rest of your argument boils down to, "if a lot of prominent people in a field believe something, it must be because there is a lot of merit-based evidence". That assertion is completely false. Merit-based evidence is one of the ingredients that lead to consensus, but hardly the only one.

[betwixthewires]

I see your point, but I think the person you're responding to is trying to say that he is not saying "if a lot of prominent people believe something then it must be because there's a lot of evidence" but rather "there is a lot of evidence, that is why so many people believe it." The difference there is in actually being able to show you the evidence rather than just telling you to trust a priesthood. I don't think that the person you're responding to is using the consensus in place of the evidence, but rather telling you that if you look into it deeply you'll realize why the consensus exists.

[amanaplanacanal]

The consensus is not always correct, but unless one becomes an expert in the field, betting on the consensus being right is probably the way to go.