Olympic teams are like private clubs, and they can do whatever they want to run their clubs.
But when people get caught doping, or using steroids, they get disqualified. Even if they would have won the medal without the juicing. It's about integrity.
The DNC had rules, and they broke them to keep Bernie from winning. The colluded against his campaign, engaged in voter suppression and voter fraud, and even got debate questions in advance.
Regardless of the "fix", the fact is that the DNC has lost all credibility. The insurgent who fought the Republicans won because the Rs played by the rules they set out. The insurgent who fought the Democrats lost because the Ds didn't play by the rules they set out.