The right to free speech is enshrined in the Constitution, yet we place restrictions on speech that are generally uncontroversial. The framers said nothing about restricting child pornography, but it has been held to not be protected speech. The framers made no exceptions for incitement or fighting words but they have held to not be protected speech. The framers made no exceptions for obscenity, but you still can't play George Carlins 7 Dirty Words sketch on the radio or on television without getting fined and risking your broadcasting license.

Yes, the 2nd Amendment gives a right to bear arms, but it does not give a right to bear arms sans any regulations or restrictions.