Final answer:
Martin is embarrassed by his grandfather's behavior due to the latter's deference to social hierarchy, reflecting outdated beliefs about class that conflict with modern progressive attitudes.
Step-by-step explanation:
Martin is embarrassed by his grandfather's behavior because it reflects a mindset and a social dynamic that is seen as archaic and inappropriate. The text suggests that his grandfather exhibits deference towards the wealthy and well-born, indicating a sort of ingrained classism or bias. This likely causes embarrassment for Martin because it suggests that his grandfather holds outdated beliefs about social hierarchy and possibly lacks the progressive mindset that is more accepted and expected in modern society.
In the context of the passages provided, there's a theme of individuals being influenced by their heritage or the social environment around them, which complicates their personal identity and behavior. The mention of hereditary evils, the colonel's misplaced trust, and the characters' reactions to the social inequities of their time all highlight complex relationships between personal beliefs, societal influences, and individual actions.