As has been mentioned..one rule says you must give your horse every chance. If you have a speedy squib running a slow first half is giving your horse every chance.
There are also rules against fixing races yet saying you have to run <64 is indeed fixing how a race is run.
I get why the rule is there, too make it a bit easier for backmarkers in a leader dominated sport, but I think it's up to the drivers. I know sometimes going forward may not come off and drivers can look like gooses but at the moment all the drivers are like robots. A drive like John McCarthy's on Mach Wiper a couple weeks ago earned himself a thread, it was a good drive indeed but we should be seeing way more good drives to the point it isn't really threadworthy.
That was a front running example; for a swoopers example just watch Mick Hardy at places like Wagga and Young. I would rather back Mick Hardy when he has to go back then when he is drawn to lead! He is amazing at timing his run and getting home. If Hardy can do it on those half mile tracks where the leaders walk half the time then surely the 'big names' can do it at Menangle.