While I understand what you mean when you say they shouldn't be titled synthetic cannabinoids especially since a lot of people are uneducated about cannabis (which has phytocannabinoids with a relatively good safety profile) but if they are called synthetic drugs then the public could relate them to the medication they take which might be created synthetically, some people won't know the difference, and who knows if that may make them scared to take their medication in fear that they could have a response like people have to these cannabinoids.

And the chemicals themselves are also slightly similar as they act mostly on the cannabinoid receptors, while tetrahydrocannabinol is a partial agonist to these receptors, most synthetically created cannabinoids are full agonists. So they are pretty similar, but yes the effects of the synthetic cannabinoids commonly found in New Zealand are stronger and very different to cannabis (not from experience, but the chemicals are known to have a higher potency.)