Complex sentence: Mental hardness (laconicity, terse coherence of thoughts) was regarded as masculine, whereas mental squishiness (incoherent loquaciousness) was regarded as feminine or infantile--to become a man, a male child had to harden his mind.
Split into simpler sentences: Mental hardness (laconicity, terse coherence of thoughts) was regarded as masculine, whereas mental squishiness (incoherent loquaciousness) was regarded as feminine or infantile. To become a man, a male child had to harden his mind.