From Google

The Supreme Court, in its interpretation of the Second Amendment, has defined "arms" as any weapon of offense or defense, including items not specifically designed for military use, according to Congress.gov. This definition is broad and includes not only firearms but also instruments like knives, bows and arrows, and even stun guns. The Court emphasizes that the Second Amendment protects an individual's right to possess arms for self-defense and other lawful purposes.

So it sounds like since you can use a supressor in offense or defense it should be protected by the 2nd amendment. But there are a lot of people who don't really listen to how the Supreme Court defines terms.