It was used before that as a pejorative to refer to users who loaded/used code scripts, templates and programs that they neither wrote themselves nor properly understood. This included those who took other people's scripts/programs and edited/changed variables and snippets here and there.

It differentiated the 'real programmers' (that is to say, those that could actually author/write/understand programs and original source) from those who were, for lack of a better word, code stealers and copiers.

I say this as the kid who undeniably was a script kiddie back in the early 90s and on irc and got started in coding from doing exactly that from the late 80s onwards. Can only absolutely place the phrase script-kiddie from mid-90s however, but might explain why i never did really 'get' what people meant by scripting language...