.planting_team and .defusing_team are just strings, it's only text "allies" or "axis"
and the addkills command can be used on one player at the time.
you need to loop through all players and give kills to the players on the planting team
something like this:
for (local.i = 1; local.i <= $player.size; local.i++) {
if ($player[local.i].dmteam == level.plating_team) {
$player[local.i] addkills 2;
}
}
I'm not sure if this will work with level.plating_team, maybe you need to change it to the "bomb planter" .dmteam