> Tldr: If you aren't a paramedic or higher, you shouldn't be administering insulin or dextrose/glucose either way.

Quickly checked current Australian and uk first aid resources (red cross training), and they do still seem to recommend that first aiders do it (giving sugar/sugary foodndrink) assuming the diabetic person is still responsive. I'd maybe be a bit more careful with wording when giving medical advise or first aid training online without being very specific as to where it applies.