Back when they came out with Hybrid Theory they were definitely metal. Later on it's not so much metal, And then Chester died. That was unfortunate, But still I feel like the mellower music could have just been from him struggling more with depression. It has a lot of aspects of metal, So there's no reason it should not be considered that.
Metal is a very broad genre, And it is not limited to just death metal bands who can growl. And even if it was, Just listen to the bridge on the song "Faint" and it has the same aspect of the vocals. Sure, They did have a period of time when they were no longer metal, But their nu metal music is still metal. If you can call Metallica metal after knowing how they sold out, You can still call Linkin Park metal. I don't believe Linkin Park really sold out, They just changed their style in a way that was coincidentally more radio-friendly. And, As much as I hate to say it, Nickelback is metal too. They had their days of being metal before and after their time of popularity (still didn't make up for "Photograph" though). Deciding rock from metal can be a hard thing to do, And although it's easy to classify bands like Amon Amarth as metal, Other bands are more difficult. The way I think of it is, If you listen to someone like Linkin Park and say, "This is metal", Then it's metal. If not, That's up to you. But, Despite being into death metal/black metal music, I still think Linkin Park can be considered as metal.
Some people say that Linkin Park is rock, some of it is, but not most of it, its early albums, Hybrid Theory, and Meteora, is rap rock and nu metal, in my honest opinion, its average genre is alternative metal, what bothers me is when people say it's pure rock, because thats not necessarily true
“You have to be kidding me! Linkin park on the top metal tracks? They are not even metal!” And I am going to support this opinion. While many people consider them metal, they are technically not. They can throw up the horns all they want, but they are still only as heavy as Nickle back. These guys would be considered more of rap rock. Much different from metal. And you may argue, “YES THEY ARE METAL DERRR UR AN IDIOT HEHEHE” well, what do you mean by metal? Do you mean Heavy metal, death metal, nu metal, etc. While many people say that they are nu metal, the closest thing to “metal” that they have is modern rap metal. And a bunch of people consider it “poser metal” I would honestly agree with them, but I’m no elitist!
Linkin park might be metal, it might not be, it's simply music. It's quite annoying to see lots of people trying desperately to categorize music, especially when the band in question has a unique style. Unfortunately this happens quite a lot with labels such as "metal" and "electronic". As for the person saying "some people say it's rock", metal is in fact a sub-genre of rock, so you will have to be more specific.