When a question asks about the validity of a single source, are outside references strictly required

Question

An answer I gave was deleted by a moderator. The question asked specifically about the validity of a single source, which claimed to be a clinical study of an alternative medicine treatment.

My answer discussed the experiment this study did, and stated that the experiment was not valid.

The first reason the moderator gave for deleting my answer was, "Firstly: you provide no evidence, you only cite their study."

The question asked "Does the study described on the product website support the claim that the product prevents sunburn?"

Is it skeptics.se policy that an answer must cite more than one source?

Related, but concerning a single high quality source.

Answer 1

Thanks for bringing this up on meta.

You are correct to think that outside references are not required. However if you want to add conclusions, such as asserting the product tested by the trial does not work, that requires evidence of such conclusions and dismissing the study is not enough: a bad study doesn't prove anything either way.

For example. "water memory" (homeopathy) is as ludicrous a claim as "scalar waves water", and it took the scientific community years of studies to disprove it! While we all feel that the claim posted is "ridiculous", on skeptics we need to stick to the evidence and limit our conclusion to what is actually proven by evidence.

To be clear, this is the reason why I was initially trying to edit your answer, in the hope that a slight rewording might make it clear that the product is merely unproven to work and not proven not to work, but I ultimately decided to delete it because of the other points I made in the comment under it. Fundamentally that you are debunking the study by making many novel claims yourself. Those require citations, which you haven't provided.