That's an interesting theory and it is certainly an issue worth investigating. Jeffrey Hummel did not shy away from documenting southern abuses of liberty during the war in a book that heavily criticized Lincoln's cause and similar abuses. From my own reading and research I have to conclude that, while abuses did indeed occur in the south, they were comparatively lesser than those in the north on several counts.
You mention Bensel's conclusions on taxation, which strikes me as odd after having studied the tax laws of both countries. Statutorily, northern tariff rates - the primary source of revenue for countries in the 19th century - ranged some three to four times the southern rate on the exact same product.
The habeas corpus issue is interesting and also widely misunderstood in both the north and the south. Both at times suspended the writ but they also did so through very different procedures. The north suspended it by a unilateral, not to mention unconstitutional, decree from the president. Attempts to reign in its use through the federal court system all resulted in rulings against Lincoln's authority to do this but he simply ignored them and continued carrying out the suspension. The south, by contrast, passed a suspension of habeas corpus through the Congress for limited areas and periods during the war. Though any suspension of the writ is no friend of freedom, the confederate suspension was a lesser offense than the union suspension for one key reason: the confederates did it constitutionally by act of the legislature.
In my experience, a common misunderstanding of the southern political system has led many to incorrectly overstate the degree of southern abuses. I have not read Bensel's book though I do suspect he may suffer from the same simply because this error is so widespread. It is widespread because the concept it mistakes is largely foreign to modern day concepts of American government. So what is this misunderstanding? The neglect to accurately represent and account for the presence of state sovereignty-oriented federalism within the confederacy's political factions. A strong and sizable portion of the confederate congress subscribed to this ideology throughout the war, leading them to constant political fights with the contrasting ideology, which closer resembles what we think of as the federal system today.
On the one hand they had a faction, represented in action by Davis and his allies, which saw the CSA federal system through a national orientation with national sovereignty reigning supreme. It battled the states-righters, who literally saw the CSA as a confederation of independent and equal sovereign nations. These were the types who subscribed to theories of nullification and the sort. They were represented in the governors of several states, such as Pendleton Murrah of Texas. They also had a significant and sometimes majority faction led by Louis Wigfall, also of Texas, in the CSA senate. This second faction weighed in heavily on several of the areas where national abuses of liberty are commonly cited: habeas corpus, the draft, the role of a court system. The states right senators and several state governments believed that the federal legislature only had the power to suspend habeas corpus in the federal courts. Thus they supported the bill to suspend it nationally yet continued to issue writs in the state court systems, in some cases undermining the national policy. They also supported the national draft but in doing so argued that members of state military units (militias and home guards) were already in the service of their respective states and thus exempt.
Some modern scholars have also railed against the confederacy for not establishing a supreme court system as if this deprived its citizens of judicial recourse for their rights. They do so because they view the judiciary through the lenses of a modern post-Earl Warren ACLU driven U.S. Supreme Court. Put differently, they see the entire purpose of courts as being a place for people to go and sue for something that they feel they are entitled to own or use but have been unjustly denied. Sadly, this modern rendering could not be further from the understanding of courts as seen through they eyes of confederate states-righters.
In reality, it was the pro-national faction of the CSA - Davis, Benjamin, the administration - who fought for and advocated the establishment of a strong supreme court. They did so not because the court would be an agent of recourse against the federal government. They desired the court so that it could overrule state governments that obstructed national policy. The states-righters did NOT want the court and successfully blocked the bill establishing it. This not because they wanted to deny recourse against the government. Rather they desired to prevent the federal government from centralizing power at the expense of the state governments. They feared a CS supreme court doing what John Marshall had done in McCulloch v. Maryland so they prevented it from being established and routed all the cases through the court systems of their originating states.
Absent an understanding of the state-oriented federalism theories in the CSA one would not know this to be the case of the supreme court. Viewed through modern Earl Warren glasses the absence of a court seems like an eggregious violation of liberty and recourse. But viewed through the eyes and judicial philosophies of the mid 19th century and the exact opposite is true. Sadly, modern academia tends to prefer the Warren glasses at the greater expense of historical accuracy.
To note one example of this that comes to mind - and beyond this I won't bore you anymore in this increasingly lengthy post - there have been two biographies written of Wigfall, who was arguably the most influential member of the confederate senate. One is written by his daughter and contains her personal recollections through the war. The other is a standard modern biography by a scholar. His modern biographer, though a thorough researcher, failed miserably to even breach into the basic mindset of his subject. Instead he sees virtually everything from a modern post-1960's understanding of government. He rails on end about Wigfall's successful efforts to block the CSA supreme court and his support of the national habeas corpus suspension while failing to substantially account for what I have just written of. The resulting picture is of a power-wielding agent of harsh government policy when the real Wigfall was a radical states-rights advocate who constantly worked to oppose the centralizing forces of the administration that, to him, came at state expense.
How free can you expect a country to be when a foreign invading army is maneuvering about freely on your land, laying waste to your resources, while at the same time your coastal ports are being blockaded? Turn the tables and the conclusion would be the opposite.
And the reason the South is winning now is because it is more free.