Libertarianism is all about antinomianism, and with it the incremental abolition of statism (as the only supposed legit excuse for human ownership and violence). In simple terms it is all about individual freedom which is exactly where free(wo)men and libertarians meet.
While Libertarians and FMOTL have a few things in common, there is a world of difference between them.
1) Libertarians believe victimless crimes should be repealed but we have to follow them until that time. FMOTL believe that they may simply ignore such laws because the current government has no jurisdiction over them.
2) Libertarians believe the current tax structure is an unjust and violent violation of our natural rights, but until we repeal such laws, we have to pay the taxes. FMOTL believe that they may simply ignore such taxes because the current government has no jurisdiction over them.
3) Libertarians believe that there are legitimate needs that only the government can meet - such as providing national defense (with a much smaller military), ensuring a fair criminal justice system (including courts, appeal courts, and prisons), issuing passports, maintaining the borders. FMOTL on the JREF have argued that none of those tasks is a legitimate task of government.
4) Libertarians believe that if you receive a court order to appear and your name is in capital letters, then you have to appear and the order really is correctly identifying you. FMOTL believe that the difference between one's name and one's name in capital letters is so radically different that they don't have to respond in any way to such court orders and summonses.
5) Libertarians believe that when facing charges related to a victimless crime, one must follow the rules of the criminal justice system while making use of all the defendant rights available in the Constitution and other law. FMOTL believe that they can say latin phrases to make the court tacitly or explicitly admit that there was no valid legal reason for the charges before dismissing the defendant.
If you like, I could go on (admiralty courts, birth bonds, gold-fringed flags, etc.). Many on this board may disagree with Libertarianism, but no one here believes it is in the same ballpark as FMOTL.