Final answer:
The line emphasizes the challenges of changing deeply ingrained beliefs and attitudes in others and suggests that change must come from within, not through forceful means.
Step-by-step explanation:
The line "you just can't force people to change their hearts, son" highlights the challenges of trying to change deeply ingrained beliefs and attitudes in others. It suggests that change must come from within, and external pressure alone is not enough to transform people's hearts. This idea aligns with research on persuasion, which shows that people tend to change their attitudes when they are persuaded through understanding and meaningful communication rather than forceful means.