But they are wrong, even from a grammatical/syntax stand-point.
In the 2nd Amendment, the “militia” statement is part of a DEPENDENT clause. It is, therefore, not capable of standing on its own as a sentence.
The “right to keep and bear arms shall not be infringed” statement is contained within an INDEPENDENT clause - that is, it has meaning as a complete sentence, even when standing by itself.
Grammatically speaking, dependent clauses do NOT control the meaning of independent clauses when they appear in they same sentence. They may clarify or enhance the independent clause, but the independent clause controls the overall meaning/intent of the sentence as a whole.
Thus, the right to keep and bear arms is NOT in any way dependent on service in a militia and it never has been.
Confusing the grammar, they are.