No more aggressive than the north.
Massachusetts had slaves from the early 1600's. The state never passed any legislation outlawing slavery. In fact, they discouraged it. People now claim that slavery was ended in Massachusetts by state supreme court. That really didn't end slavery there. People who wanted to free their slaves had to post a bond to ensure that the freed slaves didn't become a burden on the community. Families called them servants. Just changed their names.
Much more than just the names -- servants who are paid a wage and can quit their jobs are, by definition, no longer slaves.
A 1754 Massachusetts census recorded about 4,500 slaves, but from 1790 on none were recorded (except one in 1830).
In 1860 Massachusetts had about 10,000 freed-blacks.
By 1860 Massachusetts, Maine, New Hampshire, Vermont, Rhode Island & New York allowed free black men to vote.
The institution of Slavery was the fabric of the entire economic system of the south...without slavery their economy would collapse. You are picking at straws. There were no slave plantations in Massachusetts and no cash crops like cotton and tobacco that were picked by the slave labor system of the south. That is what the South was defending when they seceded.