black-and-white

mustavalkoinen

mustavalko- Of art, a photograph or photography, using shades of grey/gray rather than colour/color.
Of a television or monitor, displaying images in shades of grey/gray rather than colour/color.
puhekieltä classify Classifying people, objects or concepts as two polar opposites, especially "right" and "wrong"; dichotomous and inflexible.
1999, Cynthia Hendershot, Paranoia, the Bomb, and 1950s Science Fiction Films, Popular Press (ISBN 9780879727994), page 28

The pseudo-community of enemies in The Day the Earth Stood Still consists of politicians, the military, and businessmen, whereas the pseudo-community of friends, the element that complements the enemies and reinforces the black-and-white morality of paranoia (Cameron, "Revisited" 56), is composed of scientists, women, and children.

Security people are often the black-and-white kind of people that I can't stand.

“It's complicated. Not everything is black-and-white, Ginny. Sometimes, it's just gray.” The disillusionment in Ginny's eyes hurt bone-deep. She was a black-and-white kind of person. Actions were either right or wrong. No room for in-betweens.

You could say that inflexible thinking is black-and-white thinking and flexible thinking is rainbow thinking. Black-and-white thinkers have difficulty being flexible in their mind and seeing different possibilities and perspectives.