This answer is definitely unfriendly and something needs to be done to it, but (I haven't seen this specific Q&A) is it really worth receiving a blocked/hobbled IP address and -100 reputation? Rude/abusive flags are 'heavy' tools and shouldn't be used lightly. This is a slightly different situation than comments, where we have a 'soft' R/A flag in the form of the 'unfriendly or unkind' option.
Since this post does seem to attempt to answer the question, albeit in a very generic way, a 'Not an Answer' flag isn't warranted either.
If I encountered such a post, I might have edited it into something like
Questions like that aren't likely to give you reputation. Please read the help center to improve your questions will get upvotes, and in the end try using the homepage frequently and help the others with good answers.
and it might be that the ♦ moderator handling the flag thought you should have done so as well. You don't have the edit privilege (yet), but it's easy to miss that from the flag dashboard. And you could have suggested this as an edit.
I felt this didn't really fit with being nice as it uses an exclamation mark
Punctuation is used differently by different people. This particular instance might be inspired by text messaging, and scientific research confirms that ending your texts with a period is terrible. Anyway, it's typography and something which can be improved by editing.
and tells people basically not to ask a question.
No, it tells people that a specific question is bad, which is an opinion and one which can be backed with objective criteria. Again, without seeing the question, chances are high that the person who wrote that answer is actually right about that. Furthermore, it even offers some guidance on how to improve the question.