6:00 PM PT -- A rep for Questlove tells us he denies the "ridiculous allegations" in this suit, adding ... "Racism is REAL and exists throughout the world and for these gentlemen to claim victim is not only disrespectful to Questlove and his band mates, but to all that truly endure racism on a daily basis."

3:36 PM PT -- A rep for NBC tells us, "NBC is committed to providing a work environment in which all individuals are treated with respect and dignity. We have strong policies in place that protect against discrimination in any form. The decision about these plaintiffs was the company's alone."

Questlove demanded NBC fire two white camera guys on the 'Tonight Show' over a racist group text they never asked to be a part of ... this according to a new lawsuit.

Camera operators Kurt Decker and Michael Cimino just filed suit against the TV network and the leader of The Roots after what they claim was misappropriated blame and racial retaliation from Questlove after each of them received a racist text he caught wind of.

According to the docs, obtained by TMZ, a stagehand sent Decker, Cimino and Roots member Mark Kelley -- who's black -- a text during a taping of the 'Tonight Show' last year, which they say they never asked for or responded to. They say they tried explaining this to NBC execs in an attempt to distance themselves from the vile text, which they feared would be associated with them.

Questlove got wind of this and demanded that NBC fire the camera operators, which NBC did.