"reduce the amount you
report on line 7 by those contributions."

The issue for MA (and likely some other States) comes from who pays the Sick Leave premium ("contribution") because sometimes it is the employee (and pre-tax means you don't also get to deduct it from the payout), post-tax, employer, both.

"Massachusetts’s PFML law is funded through employer and employee contributions, and is different from the federal Family and Medical Leave Act, and from any benefits your employer might already offer."