Functionally speaking Zanna's answer is good... Although I would beg you avoid rollback wars.
That is to say if they rollback your rollback, don't rollback again. Raise a flag for a moderators on your post. Explain the problem and we'll find the rustiest spoon available to "deal with" the problem. We're good at wet work. Use us.
On a slightly different tack before you blindly roll things back, make sure they haven't left you a reason for the edit. The situation you describe sounds like you've copied a load of content that isn't yours and somebody is scrubbing that from the post.
Let us be clear here. Posts you submit here grant everybody else a license to that content. If you don't have the rights to that content (or a license that gives you permission), you are committing copyright infringement. By extension, because SE is providing this content under a license that allows people to use redistribute, they become [slightly] liable for the content too.
So anything you post that isn't yours either needs to be:
- Small and discrete and important enough that it fits under fair use.
- Used under a license compatible with CC-BY-SA v3. And in the way that license specifies.
If you are using another SE user's posts, as you are in this post, you have to follow the SE license to the letter. There are 4 attribution requirements:
- Visually indicate it's from whatever SE site it's from (eg "This is a post from Ask Ubuntu")
- Link to the original question (or better yet, the answer).
- Explain who wrote the post you're copying. All its authors.
- Link to each author's profile page.
In this example of yours, you're only completing step 2. That's not good enough.
And that's with quite a permissive license. If you're copying from something that has no open license (all work is assumed copyright unless otherwise stated) in a way that is well outside the scope of fair use, that's even worse.
Either way, tidying up copyright compliance issues is a perfectly valid edit but they should explain this in the edit reason or comments.
Copyright infringement isn't the same as plagiarism.
Everything above is about copying actual content. It's a legal hurdle. In that regard it is very different to our policy on plagiarism which deals with the much softer side of being honest about whose ideas it is you're using and giving credit where due.
So yes, this has similarities to the attribution requirement, but this applies for much smaller things and is completely independent of the copyright license. Even if something were explicitly public domain, CC0, etc and didn't require attribution, we would still expect you to list them as the reference.