I'm just extrapolating here.
In a small group, everyone knows everyone and the chances of some politician or lobbyist manipulating the system would not be high because they'd be too easily caught. However, when you have a huge group, very few know each other and people will find ways to get into the system and manipulate data or election results. It's human nature. Cheats are born every day and they just have to find ways to game the system.