The attack wasn't as targeted as you seem to think. It also hit health workers and bystanders. Approx half the casualties are civilians (including children).
According to Humans rights watch: https://www.hrw.org/news/2024/09/18/lebanon-exploding-pagers...
> Thousands of pagers simultaneously exploded across Lebanon and parts of Syria on September 17, 2024, resulting in at least 12 deaths, including at least two children and two health workers, and at least 2,800 injuries, according to Lebanon’s Ministry of Health.