Well, the motivation to make them associative was that (==) is logical XNOR, and (/=) is logical XOR. Perhaps we want an alias for Bool-instantization of them.
We already have such an binary operation in base that is associative: xor.
>>> import Data.Bits
>>> :i xor
class Eq a =>Bits a where
...
xor ::a->a->a
...
-- Defined in ‘Data.Bits’
>>> True `xor` False `xor` True False
The thing that would be missing is an xnor operation in Data.Bits.