What is a freedom fighter? We learned in Afghanistan that this policy is actually enough to come back to bite us in the future, but there have been instances in history that funding groups of people in other countries was beneficial, and could, in proper circumstances, avert the need for full scale military intervention.
The United States already has freedom fighters, collectively known as the U.S. Armed Forces employed by the Department of Defense. Those soldiers get the stronger weaponry because they are specially-trained to wield it. To allow "self-labeled" people access to stronger weapons opens up the way for splinter groups to gain a foothold over territory they could try to take and hold by force. That's highly illegal and merits a response by the U.S. government. Just look at David Koresh and his compound and you'll see what happens when ordinary citizens wield stronger weaponry.
No, I think that the weapons that are allowed to be carried now will be sufficient fire power for these freedom fighters. Already you can own some very large guns, and they will be enough to fight off what the freedom fighters will, which they will probably never even fight.
I do not believe the government of the United States should permit self-labeled freedom fighters to wield stronger weaponry. This seems like an odd suggestion because it would simply promote civil unrest within the United States. Secondly, the US has shut down peaceful protests over the last few years so it is pointless to assume they would now let these same people have more real fire power.
No, the government of the USA should not permit self-labeled freedom fighters to wield stronger weaponry, because it would be a dangerous thing to have people fighting the wars in their own way. The rouge military combatants might not be able to do the job that the military could do, and they would likely only get in the way of the real war.