Colin Kaepernick's staying quiet. His girlfriend? Not so much.

Nessa -- the famous radio host -- posted a photo of 2 guys who have made all sorts of news by talking about her boyfriend -- Ravens legend Ray Lewis and Ravens owner Steve Bisciotti.

The pic essentially compares the two to characters from "Django Unchained" -- Samuel L. Jackson's slave-master-loving character and Leonardo DiCaprio's racist master role.

And made sure to @RayLewis.

Clearly, she's not happy with Ray's comments -- in which he advised Colin to keep his mouth shut about his off-the-field activities ... including social activism.