"Ye know not what spirit ye are of." Jesus had
come into the world to save lives, not to destroy
them.

It is possiible that John remembered Jesus' words
many times when he and Peter joined Philip in
Samaria years later (Acts 8).

If they had been permitted to destroy those who
had mistreated them, it is likely that some
of those they laid hands on to receive the Holy
Spirit wouldn't have been there to receive it.