Even among the injuries, you're still looking at an awful ratio, since Hezbollah had mostly migrated these devices out of their combatants in favor of newer models, and they were mainly in the hands of civilians.
And all of this is ignoring the blatant international law violation against booby trapping. This was very clearly a war crime.
For future reference, the specific articles:
Common Article 3; GC I Art. 12 & 18; GC III Art. 13; GC IV Arts. 27, 32 & 51; AP I Arts. 48, 51(2–5), 57 & 54; CCW Amended Protocol II Art. 7(2) of the Geneva Conventions.