Question: Going off this question [here](https://stackoverflow.com/questions/26537486/radio-button-clears-text-boxes)...

Is it ok to give a jQuery answer if the OP has tagged jQuery, but does not use it in their code? It screams "mis-tag" to me, versus "gimme dat jQuery".

More or less, should jQuery answers be valid on a mis-tagged question?

(I use the term valid loosely here, as technically all answers that aren't spam or off topic are valid)

Answer: 
Sometimes it can be hard to make grand statements about how much jQuery to use. None? Martijn's classic link depicting "needs more jQuery"?

I think each instance is kind of different and here is my take on this one.

Based on looking at this user's past history of posts they are attempting to integrate jQuery but do not really understand it very much, if at all. As a result, they tagged this question with jQuery hoping that perhaps someone would offer a solution including it so they can see how it would be used as opposed to how it would be done without using a library (plain javascript).

I think answering with jQuery is applicable in this situation, although it is definitely not acceptable to answer with jQuery when the tag is not present. I also thing that removing the tag could change the original poster's intent.
If you feel that the answer isn't helpful, you're more than welcome to downvote it. If others feel that it is a helpful answer, despite using a tool not mentioned in the question, they may upvote it. Everyone is free to provide the feedback they feel is most appropriate.

Your first comment certainly isn't inappropriate. Indicating that the answer is problematic because the question doesn't mentoin the tool used is certainly feedback you can choose to provide.

The answerer's reply of "can't you read" is starting to push the bounds of being constructive. I could certainly see it meriting deletion by a mod.

When you reply with "Are you stupid" we've now clearly devolved completely past the point of constructive discussion and into childish name calling, and nothing productive is likely to be accomplished at this point forward. Had you removed that inappropriate name calling from the comment it could potentially have had value; if you had been able to clearly and *constructively* explain why you feel the answer is problematic, then either the author could use that feedback to improve their answer, or other readers can use that information to judge its quality. But when you open with personal insults, the odds of anyone actually reading/discussing anything after it constructively tend towards zero.