[aliguori]

"Again, I hadn't lived there or worked there since 2003, but I did own part of a business that was headquartered in MA, and the state was using this fact to harass me for income tax money."

If you own a business headquarted in MA, aren't you earning income (through the business) in MA?

If you work in a different state (even if you don't live in the state), you still owe income tax for income earned in that state. This is non-resident state income tax.

Pretty sure MA has a reasonable claim here based at least on what the author states.