Nu Metal is closely related to rapcore.
Look at the "broken love"/other themes ratio of most genres. For pop, it's 90/10, for example, 80/20 goes for emo, hip-hop has almost no love, but that's another thing. You see, nu-metal DOES have love songs, but they are different from the masses, and the ratio is something like 40/60.
And why should people blame nu-metal for being mainstream-friendly? Why, in fact, is being "mainstream-freindly" bad? The mainstream is what most people currently like, and, even when its fashion goes away, there would people still listening to it.
And, who cares what kind of people are the musicians? Probably most famous classic music composers were mean bastards, but their music is still remembered. The Beatles were dope-heads, but they still are great. Understand it, nobody cares if Fred Durst is a poser. If you like LB, you like it. And if you don't, you don't.
So stop f***ing around and don't forget that music is made for people to have fun, not to argue. K?