My understanding is at one point your AG went and threatened multiple vendors/manufacturers. Their response, after looking at MA law, was probably along the lines of "WTF we can't keep track of this ever changing shit unless we hire a legal team".
However outside of that you need to consider in most states we can buy *every single thing* Aero sells - they need not think about anything beyond federal law. In MA you cannot buy *any* actual firearm they sell, you can't buy the magazines they sell, you aren't even supposed to install a flash hider on most of what is owned. 95% of gun shops in MA are gonna tell you that you can't even get a stripped lower or a Glock.
Recently I had to sit down for a minute and think if I needed to ask my buddy (lives in MA) to bring his 80% jig over the border (that I'm borrowing) so that I'm not at risk for legal problems. I have to check my truck for empty casings... Oh boy if I ever forgot I had a carry pistol, took a wrong turn, left an empty mag in my vehicle etc.. etc.. can you imagine many laws I'd be breaking?
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What I'm saying here is what goes on in MA is not normal, it's insane, strict, yet subjective and impossible to keep track of. It's completely abnormal as far as state gun laws, almost the worst in the country (top 5 worst anyway).
Seriously - I understand exactly what these companies think. Unless they want to hire a legal team to go monitor all these different states with weird laws, and they want every order to require a state legality check, there is not a practical way to stay on the right side of it. So they decide it makes more sense for them to worry about making a good product and they let the retailers, some who probably specialize in selling to particular states, supply the corner cases like MA.