The state needs more money. The straight forward way would be to raise income taxes or sales taxes, etc. But that makes the voters mad. By taxing businesses, they hope the voters won't notice and will be mad at the businesses for raising prices instead.
For the record they DID just raise sales tax, MA also requires all residents to have health insurance or you get a fine. They also are going to cut educational budget. MA is beginning to look like N.Korea...