"The state has a right to regulate interstate commerce"

First, did you ever notice that when you search for the Constitution of the United States, that it'll bring you to all kinds of government websites including the U.S. Senate website, the National Archives website, and many other government websites provide access to the Constitution, but it's almost never the full text on one page, except here: the United States Code on the U.S. House of Representatives website provides a pdf.

They break it up into multiple pages, even by Article and by Amendment so you can't read the whole thing in continuity so it's harder to understand the full meaning and the rights and powers enumerated in the Constitution.

Anyways, the "Commerce Clause" is what people are referring to when they say the state has a right to regulate interstate commerce. Let's take a look at that clause:

3To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes;

Seems pretty clear, right?

Keep reading.

The 9th Amendment. It means you can't use one part of the Constitution to argue in favor of the government curtailing your rights that are secured by another part of the Constitution.

Specifically they can't use the Commerce Clause of the Constitution to violate your First Amendment rights, (or your 2nd Amendment rights, or any other rights). They can't use the Commerce Clause to make you get a license and pay a license tax (or whatever other thing they want to call it) to exercise your right to free speech, private or professional, nor your right to meet (assemble) in public or private with whomever you want to.

The argument doesn't hold water.