To "squashed
butterflies," is to suppress or sacrifice one's dreams and aspirations in order to conform to societal
expectations.
Butterflies referring to the euphemism of "having
butterflies in your stomach", as a form of nervous excitment. To supress the things that give an iduvidual that sensation is to 'squash' them, and push away the thing that brings them joy - whether that be a person, career or particular pursuit.