Why is the former homeowner's name still on my tax bill?

Chapter 59, Section 11, of the Massachusetts General Law reads, "Taxes on real estate shall be assessed, in the town where it lies, to the person who is the owner on January 1st..."

The tax bill will carry the January 1st owner(s) name throughout the entire subsequent fiscal year.  The new owner is responsible for all taxes after finalizing the sale of the property. Tax bills will be in the January 1st owners name sent in care of the new owner. The former owner's name will be replaced with the new owner(s) name once the fiscal year has run its cycle. 

For example:   Seller A sells to buyer B. The taxpayer on record will be seller A for the remainder of the fiscal year, buyer B is responsible for the taxes due. Tax bills will be mailed as seller A , c/o buyer B to the address on record for buyer B. Once the new fiscal year begins seller A will no longer be on the tax bills.