Toxic masculinity prevents both masculine and feminine people from expressing necessary emotions, while allowing or outright promoting very specific ones in a way that's often unhealthy.

Masculine people are demonized for showing vulnerability, sadness, depression, fatigue and issues with confidence. However, men who are cocky, overly confident, aggressive, hostile, egomaniacal and angry are generally accepted and often promoted in very harmful ways.

Feminine people, however, are demonized for showing self determination, assertiveness, confidence, independence, aptitude, creativity, sexuality, happiness and passion. On the other hand, submissiveness, modesty, motherlyness, etc are all promoted.

This is because these things are what the ruling class in almost every society believes their wage slaves should do to maximize their power and profit. It's all directed by the manipulators at the top.