One argument posed by colonists against the Sugar Act was that

colonists were being taxed without representation in parliament

The argument against the Sugar Act by colonists was that colonists were taxed without any representation.

Explanation:

The Sugar Act of 1764 was intended by the British Council to cease the trade of molasses that took place between the colonists and the French and Dutch traders. The British Council looked at it as smuggling and was determined to stop it.

The Sugar Act imposed heavy taxes on molasses making it unaffordable for the colonists to buy it. Initially, this act was included so there can be legal trade and it was also for other products such as hides and skins.