I think it's a lesson about oversight and politicization of information in connection with foreign interference.
This was the first time that information about foreign interference in the American electoral process was really brought to light in the public sphere. However, that information was used for political purposes inside the country itself. So the damage was twofold: first because of the Russian interference, and second because of the American political actors themselves, who used that information about foreign interference as a political weapon, attacking the public's confidence in the democratic process.