I remember reading somewhere that it has been confirmed that defending Pokemon at a gym attack every 1.5 seconds (except it attacks twice at the beginning). Considering this, is the damage normalized so that slow and fast attacks have no DPS (damage per second) advantage over each other? For example, Fury Cutter is a very fast move, while Confusion is really slow. Does Fury Cutter's damage from a defending Pokemon increase to match the 1.5 second interval, or is it very weak in DPS?
The damage isn't normalized I believe - the only proof I have is that it wasn't ever stated otherwise and therefore implicitly stating it.
According to the Pokemon Go Database, Fury Cutter has a damage of 3 with an attack speed of 0.4 while Confusion has a damage of 12 with an attack speed of 1.51. This again means Confusion's DAS (Defense Attack Speed) is 3.01 while Fury Cutter's DAS is 1.9. By dividing the damage with the DAS, we conclude that Fury Cuter has a Defense DPS of ~1.58 while Confusion has ~3.99.
This would suggest that an attack that usually has a 5,3% higher dps actually has a ~152,5% higher dps when defending.
While those certainly are 2 extreme examples, it shows that you should use Pokémon with high Base Damage over Pokémon with high DPS to defend your Gym.
I hope I answered this to your satisfaction ~Crowley