I was on the server when this happened. Jessica warned at the beginning of the map that spawnkill with heavy will lead to kick. Then documented every kick in public chat not to repeat the failure of others. So there was some kind of warning.
On the other hand i absolutely agree to you, that spawnkilling rules are enforced in a strict way which might seem stupid. And i fully agree that there are more important rules to comply like keeping teams even (without autoblancer, and giving responsibility back to players and members to make the server fun for both teams), stop insults, ... .
I think Jessica is a great admin and one of my favorite members, but i dont like the way the whole spawn killing rule enforcement thing is going, when admins just spec spawn to warn/kick at the right time... . It is sad if game just get lost because of spawnkilling, so enforcement seems important to some. Nobody (maybe one :)) has fun warning/kicking people, that is for sure.