How would PC cdrom copy-protection even work?

I have this old need for speed high stake CDrom that just can't be directly copied by any CD-rw program, unless I use a seperate crack to get around the copy-protection. Make no mistake, the original CD itself works perfectly fine, it installs the game without a hitch. It somehow becomes unreadable when my Nero/CDrwin/easyCD want to duplicate it.

My question is: why can't a cd-rw program just simply faithfully read every bit info on the source CD-rom, and duplicate them 100% on the target CD-r?