Does "prescriptive" have solely a negative sense in some communities?
Solution 1:
Normative instruction in things like grammar, spelling, punctuation, and syntax accomplish several goals that further educational needs by standardizing on (usually written) language.
When your child says, “Mommy, I taked out the trash already,” you naturally correct her usage to the standard took out the trash. This helps her function in a society that relies upon standard English for communication. You are being prescriptive in your usage. You do this for reasons not so different from a publishing house who has a formal, written style-guide to help its editors and authors provide consistency in their treatment of English.
But what you are doing, what the publishing house is doing, is not linguistics. You are establishing a normative standard. Linguistics is about describing how language works; it makes no sense to talk about “prescriptive linguistics”.
That doesn’t mean that prescription is automatically bad. It isn’t. Sometimes, as shown above, it is both necessary and good. It just isn’t good for describing how people use language, because a prescription can never be a description. Each has its own purpose.
Solution 2:
My advice is to banish prescriptive from your lexicon.
Prescription at one time was employed by linguists as a handy name for the activity and purposes of previous writers on language, distinguished from the activity and purpose the linguists themselves were pursuing—description. In my youth, a linguist participating in a discussion like this one would have acknowledged—indeed, would probably have taken some pains to point out—that he was moving from the descriptive side to the prescriptive.
However: when the terms themselves moved from the descriptive/linguistic to the prescriptive/practical side, they took on quite different meanings. Those who stood for a less rigid mode of writing, based on popular usage, identified their activity as descriptive, and derided those who stood for maintaining the standards of the "best" writers as prescriptive.
These are the meanings which now prevail, and it's futile for you and me to protest that that's not what the terms mean to us. When even linguists (who invented the distinction) regard prescriptive as a pejorative, it has ceased to be a useful term of art; it's merely a party label, employed by Demoticrats to excite prejudice against Aristarchs.
It's a blunt tool; pitch it in the recycle bin and get a new one.
Solution 3:
Dictionaries are unlikely to provide that information, as you are referring to something that is contextual.
*“Much of the time, though not always, decisions about what is good and bad are essentially arbitrary and do not often reflect any crucial principle of language or thought.” and more.
*"Many of these rules were actually invented by someone. During the 17th and 18th centuries, scholars became preoccupied with the art, ideas, and language of ancient Greece and Rome. The classical period was regarded as a golden age and Latin as the perfect language. The notion that Latin was somehow better or purer than contemporary languages was strengthened by the fact that Latin was by then strictly a written language and had long ceased to undergo the changes natural to spoken language. For many writers of the 17th and 18th centuries, the rules of Latin became, whenever remotely feasible, the rules of English.
It is somewhat surprising that rules that do not reflect actual language use should survive."
*"Linguists tend to view prescriptive grammars as having little justification beyond their authors' aesthetic tastes"
*...prescriptive rules are, at best, inconsequential little decorations. The very fact that they have to be drilled shows that they are alien to the natural workings of the language system. One can choose to obsess over prescriptive rules, but they have no more to do with human language than the criteria for judging cats at a cat show have to do with mammalian biology.
*Confirming simchona's comment: "Moreover, in order to obviate the messiness of exceptions, pedagogic grammars tend to be more assertive than they need to be – often at the cost of accuracy. Rather than stating rules, they issue edicts. (Perhaps they should be called ‘pedantic grammars’)."
I could go on forever with examples of why 'prescriptive' is a considered bad word in the language community, equating pretty much to pedantic or uneducated, with an implication of an uneducated little man (probably a schoolmaster), devoid of understanding, parroting something he read in a book. This may have been true 100 years ago, but believe me - we have moved on. Nobody wants that 'prescriptive' label.