Just take it from other way - lets say "dodge" rune gives you very strong bright light, while Block is covering your body with stone. Now think about it - even if you stun that target, your next heroes still can miss hit and enemy will get "dodge" cus his light still blinds your guys with a % chance xD Also you can manage to still hit him, but his armor can block your attack if you will hit "stoned" zone. I hope it helps xD