There is a difference in that sugar is mostly protected with quotas, while corn is protected by subsidies. (although there are some subsidies for sugar as well).
So the effect is that government intervention causes sugar prices to go up and corn prices to go down. Thus, there is government interference on both sides of the equation.
I consider corn subsidies more problematic, because they come directly from taxpayer money, while the costs of sugar tariffs are more roundabout (i.e., they result in higher market cost of sugar, but are not taken from my tax dollars, thus one can avoid the cost by eating less sugar). Also from my limited research it seems that corn subsidies are much more costly than all the cost of sugar price support.
I don't know much about the history of farm subsidies but on the point of government intervention perhaps it made sense at some point in history but its time has past. Anyone who tends to argue for government intervention / regulation is usually pretty realistic about the need for the policies to be continuously adapting and evolving over time. It'd be silly to think we should never revisit these policies just because they've become the accepted political status quo. I'm a fan of any regulation / intervention to come with built in sunsets instead of being considered something that will stay on the books indefinitely.
One might assume that since our government now says that healthcare is a right, they might also say that it's time to end tariffs that are demonstrably damaging our health.
Unfortunately, that's going to require our government to step up and admit that they have been grotesquely and aggressively wrong about dietary issues for fifty years now.
I'm watching the murmuring about taxing soda; I'll know they're just bullshitting us about the health angle if it taxes sodas with no sugar in them, too. (I've read the health evidence about mere carbonated water; it's a non-zero risk (mostly potential lower esophagus damage caused by excessive belching spreading stomach acid around) but minimal next to the risks of obesity.)
So the effect is that government intervention causes sugar prices to go up and corn prices to go down. Thus, there is government interference on both sides of the equation.
I consider corn subsidies more problematic, because they come directly from taxpayer money, while the costs of sugar tariffs are more roundabout (i.e., they result in higher market cost of sugar, but are not taken from my tax dollars, thus one can avoid the cost by eating less sugar). Also from my limited research it seems that corn subsidies are much more costly than all the cost of sugar price support.