
At least in this picture, it is because Rusty is smooth. Look at his legs and delts in comparison. The other guy is cut much deeper and has lines on his delts.
However, since the overwhelming majority seem to favor a pleasing structure over ripped-to-shreds, maybe (Bob) the judges aught to conform to public opinion and weight things differently.
Give more points to body structure (which, as seen here, people seem to favor) and fewer points to conditioning (again, people don't care so much about).
A side benefit to such a change in judging would be that the genetically superior competitor would win (drugs do not help basic structure). And, drugs would mean less (at least cutting drugs), therefore aversely affecting competitors health less.