Q:

Reference to Policy "`not-` tags inappropriate on this site"?

A user has claimed that:

not- tags are inappropriate on [StackOverflow].

Can anyone provide a reference to the policy/decision to which he refers?  Or is he just stating an opinion?
For example there is a tag I created, and he edited my question to remove it based on the above.  Under what circumstances do I have the right to rollback his edit if I disagree with the change?
Background: Almost any question asked in the Algorithm tag can seem like a homework question and many times randomly these questions receive a "Is this homework?" comment, almost always from someone that has never asked a question and never received a answer in the Algorithm tag, which is extremely annoying.  I guess I will simply continue to ignore this question.

A:

Most not- tags would be meta-tags as classified by Death of Meta Tags:

If the tag can’t work as the only tag on a question, it’s probably a meta-tag.

You can't tag a question with only a negative, you'd always need something more to define what "category"/"area" your question belongs to. (homework is a meta-tag with a long history of debate attached to it.)
See: How do I correctly tag my questions? – don't create meta-tags. Tags are there to classify, to help searching, to get tag-experts to look at your question. I can't see anyone following the not-c++ or not-jquery tags.
If you are after an answer that doesn't use LibraryX or some specific feature from your language or framework, state that in your question (possibly with a reason why if that would have been the most logical thing to do/use). But negative tags aren't a good idea at all IMO.

A:

How can I write to the console in C#?
I would have added more tags, but there are only five allowed. :(
c# not-java not-winforms not-textbox not-homework

No, they're definitely not useful. Tags should describe what your question is about, not what it is not about, and especially not what your intentions are (or not). That the homework tag exists is a pure edge-case which should be reconsidered sometime.

