This is not the case so why f#%k with it by turning on an enhancer? I've only heard it degrade the sound with lossy material but some may hear an improvement and leave it on. Compressed or not, it just isn't necessary for lossless material and blasting an enhanced MP3 track is never a good idea as these tracks will receive the most "enrichment". Results and opinions will vary among different AVRs and listeners. I prefer to leave it off.
Though, I do appreciate the link to eight year old material regarding the process.