Massachusetts bars the possession of firearms or "ammunition," which includes pepper sprays, unless one has a firearms identification card -- and it bars aliens from getting firearms identification cards. Mass. Gen. Laws. ch. 140 §§ 121, 129B, 129C. And Massachusetts completely outlaws stun guns for civilians. Mass. Gen. Laws. ch. 140 § 131J. The one possibly relevant exception (I set aside an exception for target-shooting competitions) is that "The colonel of the state police may, after an investigation, issue a permit to an alien to own or have in his possession or under his control a rifle or shotgun; subject to such terms and conditions as said colonel may deem proper." But that's entirely within the colonel's discretion, and is limited to devices that are both deadly (pepper spray is excluded) and can't be easily carried in public. Please let me know if I'm misreading these provisions.
Yet the Massachusetts Constitution says, "All people are born free and equal and have certain natural, essential and unalienable rights; among which may be reckoned the right of enjoying and defending their lives and liberties." Many states with nearly identical provisions have interpreted them as securing a constitutional right to self-defense and defend property (subject to traditional limits barring the use of excessive force, such as deadly force in response to not very grave threats). The matter has never been litigated in Massachusetts, but the text seems quite explicit, and the precedents from other states on point. But despite this Massachusetts law seems to take the view that non-citizen people can be limited to defending their lives with their hands, or maybe other items that come to hand but that aren't optimized for use as actual life-defending weapons.
Kind of like telling people that they have a right to prevent conception, but only using the rhythm method plus maybe Saran wrap. Except of course that the right to defend life is expressly mentioned in the Massachusetts Constitution, so that there should be no controversy about whether such rights should be protected as unenumerated rights (which has been the case as to contraceptives).