That was an oversimplification, yes
Mind you, Sha3 is different from scrypt and i can confirm that the cpu usage is from the sha3 cgminer and not a wallet with setgenerate turned on.
I couldnt tell you exactly why sha3 uses cpu like it does, but there are no negative impacts observed by the dev team, so we quite like the algorithm
What I'm saying is that I get essentially 0% CPU on the sha-3 cgminer. If you're seeing high CPU then something is wrong.

Are you seeing this issue on Windows or Linux?
Seems exceedingly common on winderps. Dang amd drivers some of the time....