To be fair, Sephiroth couldn't quite lay the SFF beating on Vincent/Tifa back in 2010 too. Cloud/Sephiroth are probably hated to the point where the voters are more inclined in voting for the weaker character from the same series/game over them just for the lulz.
In short, Cloud/Sephiroth aren't capable of scoring blowout or dishing SFF as well as Link due to the nature of anti-voting.