Nowadays, most uses of the term "precious snowflake" are derogatory, such as the following tweet from a pro-Trump Twitter user:
Here's a clue. Get some backbone and stand up for America, by rejecting the precious snowflake SJWs. But that won't happen, will it?
When the term was originally used, was it derogatory, or was it originally positive and turned into an insult?
The term is too recent for the Online Etymology Dictionary, and isn't mentioned in any dictionaries indexed by Onelook apart from Urban Dictionary