They want to avoid algebraic attacks

And addition is very cheap way to get high multiplicative complexity on commodity hardware.
Don't they have rotates for that?

Cheap in software, free in hardware.
And this is a question from someone with bitslicing experience?

Smolen... that's called lazyness

reorder was making a joke about some hashes using addition without really caring about the additional properties of addition comparing it to XORs because a hardware adder is just an XNOR with some ORs looky here
http://en.wikipedia.org/wiki/Adder_(electronics)
Oh, damn, those "additional properties" almost drove me mad
