The purpose of the voting system is to resolve the disagreements in the fairest way feasible.
and the fairest way is the one that satisfies everyone, not the one that “suppresses” the others (through negative vote, which cancel each other out).
I favor A and oppose B and C, but you have the opposite opinion, it takes two million (double) who agree with you to balance just one million voters who agree with me
This is wrong, in the DV:
V1 (50%): A B C
V2 (50%): A, B, C
I add the votes, I eliminate the worst ( C ), I normalize the votes (i.e. proportionally redistribute the points in each vote) and I get:
V1 (50%): A B
V2 (50%): A B
V2 is opposed V1, without the need to have double the votes and without having to cancel the V1 vote.
My definition of Opposing Votes: votes that if counted among themselves, generate a situation of equality between some candidates (i.e. only among candidates supported by someone in the votes considered; in the example parity only between A and B, C correctly excluded).