Expressing a low opinion of, for example, to belittle something or someone. Derogatory words can be used to criticise detractions, but can are usually heard in abusive outbursts of anger, recklessness, immaturity, etc.
Such language is often offensive, regardless of its original intent. Saying something derogatory may not always be greated with offense. For example, some lesbians don't mind be called a dyke. In many cases derogatory language simply states a fact or an opinion, two things which are harmless.
Trollic material, graffiti and flamebait can be derogatory. The problem with derogatory language is that is often not constructive or true. Being derogatory is not politically correct because it usually contains an expression of false discredit.
Some people think use of the terms Faux News, geek and script kiddie is derogatory. It seems the use of derogatory terms is as widespread as profanity. Some think its poor etiquette, others don't care, while some think it is deserved if used appropriately.