The key problem with the whole of the breakdown is that whilst there is a reasonable way of officiating and playing that complies with the Laws and promotes faster and for me, safer play. The Prem is long way from that.
Whilst agreeing, in the main, with the above, the problem is too often caused before the potential jackaller even has a decision to make. Listening to a lot of SH and M10 rugby, you can hear the ref calling "tackle" "release" "roll" and "ruck". Those calls allow compliance (well for me) with the Laws to be easier and more consistent
What you see so often here is that the tackled player rolls and plays after being tackled, the tackler fails to release and get out of the way, and when a ruck if formed before a defender (jackal) gets hands on the ball (released by tackled player of course....or not) a competition is allowed, with the use of hands.
I'd recommend a read and look at the WR Laws, explanations and vids - as I've prob not explained v well. But a jackal really ought to be fairly rare given the Laws as written.....