Then why does this thread say Sgt. Peppers Lonely Hearts Club Band?

What thread where? Guess what the Beatles didn't start every genre.

From the rock section:

Psychedelic Rock

Psychedelic refers to the experience the mind has when in an almost subliminal state. The boundaries of this genre are not clearly defined and spill into Stoner Rock, Acid Rock, and Progressive Rock among others. The aim is to create trippy pieces of music using vocals that either flitter or are of a low rumble. The bass is usually quite prominent to create a heavy, sedated feel and the guitar riffs are very distorted and either very jumpy or smooth and paralysing. The Beatles Sgt Peppers Lonely Hearts Club Band is the first recognised album to incorporate psychedelic features. Bands from all over the rock world can fit into this genre.

Ok but the previous examples that I stated, actually pre-dated that Beatles album.

F'k spambots.

WOW, I just got a blow job from Bar Refaeli and you don't see me bragging about it.

Does Marilyn Manson count as gothic rock? Isn't he leaning more towards industrial?

Why bother posting in a metal recommendations thread then? The last part of what you've written makes no sense either.

I'm missing a part in the metal section that sums up the characteristics of traditional heavy metal, or a better description of it. I think it should have its own part in the post, with band examples and everything.

The metal post really bugs me - what is sludge rock, and how is it the same as doom? Also, it says that power metal started in 1975, when Iron Maiden formed. Iron Maiden released their debut EP in 1979, and it didn't really sound like what the band would later become.