You live in MA, and you are asking why our legislature did something and expecting some rational reasoning??? How long have you lived here??? lol, I'm being sarcastic/not sarcastic of course, but we could name endless laws that don't make any sense.

LLCs to have the protection of a C-corp with some tax advantages, so I'm sure it's partially that MA wants their due, maybe encourage you to go with the S-Corp.