I'm amazed no-one ever brings up the GTP OLR (or SNAIL's) as a reference for what USED to pass as clean racing before we all lost our 🤬 minds and tried to delude ourselves that PD's boondoggle of a penalty system was a good idea.
Sport Mode is simply Quick Race v.2.0. And nobody with any serious aspirations to racing ever went in Quick Race on GT6.
Because GTP OLR was written by people not concerned with GT5/6 making a profit (and fixing the rules so incompetents did not feel excluded), but by people trying their best to come up with a FAIR set of rules that would promote clean racing, they are somewhat different to real racing (and totally different from Sport Mode). Contact from the rear is virtually ALWAYS the fault of the trailing car, who has a responsibility to pass cleanly. And contact that resulted in a pass was penalized on the spot by the offender returning position, or he could be adjudicated after protest and stripped of points.
Variants of these and SNAIL's rules were used in 'clean or kick' public rooms and the clean scene was so much better than Sport Mode it doesn't even bear comparison. Until Sport Mode adopts what used to work, returning position for contact that results in a pass, GTS will never be as good as GT5/6.