Why did Parliament pass the Coercive Acts?
To punish the colonies for the Boston Tea Party and other similar resistances to taxation.
The American colonies were heavily taxed after 1763; the British won the Seven Years' War (the American part of which was also the French and Indian War) chiefly by outspending the French, and intended to recoup their losses by taxing Americans for their continued protection. American colonists resented the extra taxation, coupled with a lack of representation in Parliament, and in 1773 they colluded to prevent highly-taxed tea from entering American ports. This was done most conspicuously at the Boston Tea Party.
Parliament responded by doubling down on the conditions that inspired the protests to begin with. The Coercive Acts voided locally-elected offices in America and replaced them with British appointees. And the independence movement, which had not been particularly popular among the colonists, gained major traction.