The pattern underneath
Emotion suppression plus display rules. People learn that sadness, anger, and doubt are disloyal. The short-term reward is belonging. The long-term cost is delayed help and shame about ordinary affect.
How the phrase gets misused
Anything cheerful gets called toxic. Hope, humor, and a coach who asks you to try again are not abuse.
A more precise frame
Allow the feeling, then choose the action. Positivity that skips the first step is the problem. Positivity after the first step is often health.