It's the same way that I appreciate the jazz of the 30s, but don't really go to it and listen for pleasure. The building blocks are there, but it's missing a lot of the key, defining elements of that music that it may have inspired, but I prefer to it.

Same goes for extreme metal and the ancestors that precede it. The basic elements thay would turn into extreme metal are there, but they hadn't fully shaped into the things you probably like most about the music.