The problem, I think, lies with the fact that Meteora exists. We all know what it is - the exact same style with a flute loop thrown in and some rapping taken out. When a band makes an album, I believe they have exactly one shot to not get pigeonholed into the genre of their first album - and that's to make their second album sufficiently different so that it doesn't happen. It doesn't have to be like what LP did with MTM - all they would've had to do was, perhaps, throw in more electronics, pull out the teenage angst, and bam. But no, we got Hybrid Theory Part II instead. And that's when the music critics - and the people that follow them - gave up. You make the same album twice, you'll be crawling out of that hole for the rest of your career.
One thing I found interesting is Antiquiet's review of LIVING THINGS, where it actually wasn't a scathing condemnation, but rather an acknowledgement that the band was growing out of their nu-metal loop in a natural, unforced way.
And it only took nine years.