From my experience as a Special Teams Coordinator, this has been an ongoing issue and really varies by crew/chapter unfortunately. In six-man, the kicking team must make a legitimate attempt to recover the football once it has traveled 15 yards. Contact is only legal if the player is clearly playing the ball, not just running through the receiving team.
Simply running through a receiving player who has possession or is down on a knee should be considered illegal contact since that player is down and defenseless. If the receiver has clearly secured the ball with a knee down, that is a dead ball, and any hit afterward should be a personal foul (15 yards) for unnecessary roughness. Some teams will “bunch kick” to create chaos and take advantage of that gray area, which makes consistency from officials even more important. The “commit to the ball” interpretation is where it gets tricky. Some officials want to see an actual play on the ball, while others just look for the player to be in the area.
Please correct me if I'm wrong lol?