You’ve arbitrarily chosen a word to describe something, provided...

You’ve arbitrarily chosen a word to describe something, provided a definition for that word per “a book I’m reading” and that’s supposed to be definitive in some way?

Are you reading a dictionary?

Merriam-Webster says:

Definition of cynic
1
: a faultfinding captious critic
especially : one who believes that human conduct is motivated wholly by self-interest

Of course, there will always be cynics when companies make good-faith apologies and seek to follow through.
— Andrew Ross Sorkin

2
capitalized : an adherent of an ancient Greek school of philosophers who held the view that virtue is the only good and that its essence