No it's not side-by-side. When they say side-by-side, they are talking about shoulder to shoulder because that's what teams used to do. They used to get 3-4 players and stand shoulder to shoulder to the side of the play the ball to stop any defender from even making a run towards the kicker. That's what was banned.
As long as a defender is able to get through and doesn't have to run around the players loitering and makes a run for the kicker, it's fair game. Because it's not currently illegal to loiter to the side of the play the ball in an effort to shield your kicker. Once the rule changed, teams adapted and the NRL are yet to update the rule to ban this as well. It's a loophole that's been exploited for years now.