I think the reason why that is because your accuracy never drops with melee weapons. Damaging/killing an opponent only increases your accuracy. I remember having 3600% accuracy with DOOM using only the fist/chainsaw.
To me, your accuracy being lowered for not hitting anybody with the Gauntlet or the Chainsaw is rather strange. For the other melee weapons, gauging accuracy would kind of make sense. Personally, I just think that melee weapons shouldn't be counted towards your accuracy score. The humiliation award is more satisfying. :p
