Background: adding attribution to answers
To my mind, there are several good reasons to attribute sources for answers, especially when an answer is simply a direct quote from another site:
It makes it clear that I personally don't necessarily have the experience or expertise implied in the quote. If I post an answer starting with a quoted text like "As I've observed while leading parties up the north face of the Eiger...", I want to make it clear to other users that this is not my experience, and I shouldn't be treated as an authority on the basis of this answer.
It provides more extensive resources to the reader: the whole text of a web page is usually too much to paste into a stackexchange answer, so it's useful to provide a link to the whole thing for anyone who wants a more in-depth answer.
It helps people to evaluate reliability on the basis of the source. I'll put more faith in an answer quoted from a bylined OutdoorGearLab article than one quoted from an anonymous user on Yahoo Answers.
It's courteous to the original author to provide them with credit for their work.
Conversely, I honestly can't see any downside to citing the source for an answer.
With this is mind, if I come across an unattributed answer obviously copy-pasted from another site, I'll usually edit it to add a link the source. The Help Center says "Common reasons for edits include... To add related resources or hyperlinks", and I can't think of a more directly related resource than the site from which an answer's text was quoted.
Is this a good practice? And what if the author doesn't like it?
I hadn't given much thought to this practice until today, when I noticed that one user on outdoors.se has been going through and systematically reverting any such edit I made to their answers. Here's an example:
What is the safest way to purify water (edit history of answer)
The same thing happened on How can I keep my backpack safe? and What are some good tips and techniques for packing a backpack?. In each case, the attribution link is deleted and nothing else is changed, with no comment to explain the motive for the edit.
I have two questions:
Is there some negative aspect to adding attribution which I've overlooked? Could an attribution-adding edit be construed as making an answer worse rather than better?
What should I do in a case like this, where a user systematically reverts what seem to me like clear, undeniable improvements? Post the attribution links in comments instead, to avoid "territorial disputes"? Flag for moderator attention? Ignore the whole thing? (One thing I'm not considering is rolling the answer back to my edit, because this seems likely to cause an edit war.)
I've asked the user via a comment what their rationale is for this behaviour, but I'd be grateful to get some insight from more experienced members of this community too.