That only mattered when the only weapons available to military were muskets or rifles and front loaded cannons. Today private citizens have no chance against modern American military which is part of big government. The argument we need firearms to prevent tyrannical government is laughable.
History has proven the assertion that tyrannies cannot be resisted successfully by ordinary citizens wrong, time and again. Hopefully, we will never see such as situation develop here but history's lesson is that yes, weapons wielded by individuals, have checked the most powerful militaries and tyrants and effective resistance eventually undermines an oppressor's will to fight if other alternative exist.
Effectively most of this military's weapons cannot be used against individuals without destroying that military's coherence and that country's governance. For example, callow U.S. Rep. Eric Swalwell (D-CA) mentioned that government had nuclear weapons if people actively opposed weapons confiscation. After the massive blowback, he claimed more or less that he was just joking. In reality, if the military did use an atomic weapon, on let us just say Dallas. First, it would kill mostly supporters of such a ban. The most avid opponents of confiscation are in rural areas where nuclear weapons are simply not that useful. Second, it would make the American people furious at the government as more people would be killed in a microsecond than perhaps centuries of people killed by firearms in the U.S. There would also be fallout, care for massive numbers of wounded, destruction of economic potential. Last but not least there would be a countervailing thirst for revenge against anyone that authorized and committed such a stupid thing.
The moment that any government used such a weapon against its own people would kill any moral authority whatsoever to govern--and that makes a difference as well. I also doubt that the military would want to take the blame for such an action and might well decide to get rid of any leader(s) ordering them to do such a stupid thing.
If you look at the sad situations of countries that end up fighting themselves, you will find a consistent pattern. A significant amount of the military defects with its weapons, foreign countries often get involved in supplying weapons/and or troops to one side or the other, and crude alternative weapons are invented. Humans are unfortunately uniquely able to fashion weapons of violence from pretty much anything.
Violence then does not ignore families and friends of political targets--no bodyguards can protect everyone. As the society gets brutalized, an eye for an eye becomes the standard and a country cannot effectively be ruled beyond embattled military compounds. A relatively "nice" version of this was Northern Ireland in the Time of Troubles or other areas under military occupation. In many places the British military was besieged by an angry and hostile populace and their rule extended in yards from that particular post.
The nightmare versions are that of Yugoslavia, particularly in Bosnia, in the 90's, Lebanon 1970's to the 1990's, current Syria, Colombia during the 1960's to 1990's, Spain in the 1930's, and Afghanistan since the 1970's. If you keep going back, you find countless other examples. Everyone is against everyone else, violent crime flourishes, life is cheap--your basic Hobbesian nightmare where life becomes "short, brutish, and nasty."
Far too many people are fascinated by the story of the Germans and Hitler and assume simply that a civil society will just give way to effective dictatorship. The truth is that Germans, by and large, supported the Nazi's political goals of restoring Germany's economy, order, and international status, if not the Nazis themselves.
The counter revolutionary actions post WWI, often supported by hardened former soldiers, were because violent communists that launched blood soaked coup attempts in places like Munich, Berlin, Hungary (look up Bela Kun sometimes), etc. failed after alienating most of the populations that simply wanted peace, food, and jobs, not an extension of the Russian Revolution.
There is a reason that the U.S. military did not succeed in stabilizing S. Vietnam, is not succeeding much in creating a civil state in Afghanistan, and had great difficulty in Iraq before leaving. There is a difference between holding territory against opposite organized militaries and that of fighting counter insurgencies. Insurgents, supported by a sizable population, both directly and covertly, ultimately can wear down the most powerful military by attrition. Water is softer than granite but water will eventually wear through any granite in a stream.
There is a reason that Gen. Petreaus was given command is that he understood that ultimately you must get the population on your side, not through oppression and use of weaponry, but by changing their hearts and minds. Before his command, he had conveniently written on counter insurgency failures in S. Vietnam. That is why the military would not be able to use artillery or tanks for example or bombers, helicopters gunships etc. among its own populace without failure in the long run. Far too many people are fascinated and bewitched by technology but ultimately it is people that decide what will be, not the technology. Anything invented by man can be circumvented by another invention by man.
If you are much interested in the topic, it has been developed through dry military tomes, fictionalized in novels, and appears quite frequently in academia. The general consensus is that if a large cohesive bloc (not necessarily a majority) of a population exists, it has an effective veto on government actions because almost always the cost of getting that bloc to comply will ultimately risk the destruction of that polity. Thus, in the long run, persuasion and ordinary politics is a hell of a lot cheaper in lives and money. To do that, a government must avoid conversion of political opponents into military opponents by coercive policies that leave those opponents with no alternative than active resistance. Leaving well enough alone is more effective in the long run at preserving a country's political regime and societal peace.
The problem with democracies, in some ways, versus authoritarians, is that wise authoritarians can and do back down from policies that could provoke their downfall. A political faction though, through shared ideologies, can often become so infatuated with their "virtue" that they ignore reality and provoke something that they cannot shut off once it starts. Usually that occurs because that "good think" faction becomes obsessed with making another group submit to their demands and is willing to use violence to make the resistors comply. Then, everything goes to hell.