Answer:
Because allow politicians to do whatever they want.
Step-by-step explanation:
Mitch McConnell is a well-known political, hate it for a lot of people in his field. Obviously, this type of inefficiency don't benefit common people, but politicians, that's why McConnell didn't support the decision of reinforcing the voting system security.
So, a inefficient system, at the end, benefit them, such as politically or economically.