When you use appeal to credibility "this is a real study and not just an opinion", yes, you need a peer review. Especially with how poor the quality of much unreviewed research is. Nobody suggested taking the opinion as gospel.
"Appeal to credibility"? Are we just making up fallacies based on a formula now?
Yes, given two alternatives, one should prefer the one that is more credible in light of the available information. That certainly doesn't mean that the more credible of the two is incontrovertible, but it does take more than armchair skepticism to controvert it.
Skepticism is about paying attention to all of the evidence that has been presented. Coming up with cute phrases to justify offhandedly dismissing information that you don't like falls more into the realm of pseudoskepticism.
Every string of words isn't just naming a fallacy. Sometimes words just make sentences. The person was appealing to the credibility associated with a "real study", so that's what I said.
I'm gonna assume you mean appeal to authority. As someone who has had a leg inside academia, it is shocking how frequently peer review lets absolutely methodologically horrifying studies through the cracks. Peer review is little more than a rubber stamp that enables others to be less skeptical of the contents.
The true stamp of proof in science was always intended to be replicability, but that is extremely rare to find.
