They weren't talking about pessimism, they were talking about propaganda.
The propaganda sticks because its rooted in some truth.
That the world isn't a utopian place and economic downturns happen? That was also true in the 20th century. The one with 2 world wars and a cold war between nuclear powers.
Yeah well the unfortunate truth is this pessimist generation saw their parents buy a house and build wealth with a nickel, a piece of bubblegum, and a handshake so your argument will fall on deaf ears.
It is the opposite actually: propaganda is designed to create the illusion of truth in your own mind. Kind of like the movie Inception, but out loud.