This is not from the VOX article, right?

Even with slavery, standard equality measures look similarly and historically good through the colonies. The original hierarchical social-religious projects, indentured white servitude dissipated within a few decades. The colonists were rather equal before typhoid, dysentery, labour demand. With basic survival resolved, the birthrate was high in all colonies, indicating a broad well-being basis.

Sustained inequality trends started with land scarcity within the original colonies, including New England. The Salem witchcraft episode underscored interesting religious and social-economic dynamics.

Here is a compelling resource:

1. Worries plagued the God-fearing pioneers of New England settlements

a. The pressure of a growing population was gradually dispersing the Puritans onto outlying farms, far from the control of church

b. Although the core of Puritan belief still burned brightly, the passage of time was dampening the first generation's flaming religious zeal

c. About the middle of the 17th century a new form of sermon began to be heard from Puritan pulpits -- the "jeremiad"

d. Taking their cue from the doom-saying Old Testament prophet Jeremiah, preachers scolded parishioners for their waning piety [...]

2. Troubled ministers in 1662 announced a new formula for church membership, the "Half-Way Covenant" that offered partial membership rights to people not yet converted; it dramatized the difficulty of maintaining the religious devotion of the founding generation

a. Jeremiads continued to thunder from the pulpits, but as time went on, the doors of the Puritan churches swung fully open to all

b. This widening of church membership gradually erased the distinction between the "elect" and other members of society

c. In effect, strict religious purity was sacrificed somewhat to the cause of wider religious participation (more and more women)

3. Women also played a prominent role in one of New England's most frightening religious episodes to ever occur in the area

a. A group of adolescent girls in Salem, Massachusetts, claimed to have been bewitched by certain women and a hysterical "witch hunt" ensued, leading to the lynching in 1692 of twenty individuals, nineteen of whom were hanged and one whom was pressed to death

b. Larger-scale witchcraft persecutions were then common in Europe and several outbreaks had already flared forth in the colonies but the reign of horror in Salem grew not only from the superstitions of the age but also from the unsettled social and religious conditions

c. Most of the accused witches were associated with Salem's prosperous merchant elite; their accusers came largely form the ranks of the poorer families in Salem's agricultural hinterland

d. This episode reflected the widening social stratification of New England, as well as the anxieties of many religious traditionalists that Puritan heritage was being eclipsed by Yankee commercialism

The first Great Awakening was basically the first mass movement in America, demonstrating the born American suspicion of authority - be it autocratic religion, British royal, or intellectual. It also rationalized or mitigated effects of cultivated land scarcity - perhaps the core driver of growing inequality.