Yes defending players try and get their bodies on the wrong side, which can hinder the attacking team's ability to get the ball back, and that's bad, but what about the tackled player, who always lies on the defending team's side of the ball and never attempts to roll away? These guys never get penalised! So the referees certainly aren't consistent in this sense, instead being very biased against the defending team. If they did officiate properly rucks would likely be a lot cleaner, without players falling over each other thus creating a big pile of bodies on the ground and therefore uncontestable rucks.
The tackled player has a lot less choice about where he is brought down, especially when he his brought to ground by more than one tackler.
Also, my first priority for the tackled player is RELEASE. Once he has done that, then I expect him to roll away of he can, or at the very least not interfere with the opposition.
However, there is another issue that people need to keep in mind when criticising this aspect of the way the breakdown is refereed, and that is
"who do we what to win the ball at rucks?"
If you wish for the breakdown to be a 50/50 contest with both the attacking side and the defending side having an equal chance of winning the ball at every tackle/ruck, then be VERY, VERY careful what you wish for, because the sequence of events following the implementation of your wished for policy will be as follows
1. 50% of tackles would result in a turnover.
2. Coaches will tell their players not to take the ball into contact because they only have 50% chance of retaining it. Instead, they will tell their players to kick the ball away, because they want the 50/50 contact lottery to be in the opponent's half of the field.
3. The team catching the ball will do the same.
Does any of this sound familiar?
Do we really want to return to the days of aerial ping-pong, when teams kicked the ball to each other, hoping that the opponents would make a mistake?
Do we really want another RWC final like 2007, where 80 minutes of rugby had 94 kicks in play (one every 51 seconds, or if you counted only the minutes when the ball was in play, one every 23 seconds)
This is why the breakdown will always be ruled in favour of the team tacking the ball into the tackle/ruck, because nobody wants to go back to the awful rugby we had in 2009.
What bugs me is that the new 5 second rule is unnecessary; it was only introduced because the refs failed to officiate properly with the old rules.
No, the 5 second Law was introduced for only one reason; to stop the team leading in the match (often by a small margin) doing nothing with the ball they win at the ruck, as a means to count down the clock near the end of the game.