It's true to a point, the RED isn't the best camera at reproducing colours. But then again most of the time you're going to be filming in RAW so it doesn't really matter as much since you get a flat image in post that you can grade.

An advantage the RED cameras have say over a Alexa is that they can film in 4k,5k,6k (Alexa only shoots in 2k). So that you can get a sharper image by editing in 6k, and then exporting in 4k or 1080p.

If you look at video cams for projects that need to be finished quickly, of course your not going to choose a RED. Canon Cinema Cameras (c100, c300) have the best colour science out of everyone (Sony and Panasonic are known to have pretty average colour reproduction). The only downfall with Canon cameras is that they use crappy codes and compression so when you start pushing to extreme looks, you'll get alot of noise and loose sharpness in your footage.

I use Blackmagic cameras, which aren't know for their colours either, but they own the industry standard grading software (DaVinci), so it is quite easy to get your footage balanced before you do a grade.