The only reason the income tax exists and is so complicated is because that is how the Congress gets its power, by handing out favors and punishments through the tax code.
We pay billions a year just on compliance with the tax code. We could give the Congress everything it needs for the same things it does today, much more efficiently. But if we did that, then Congress couldn't micromanage our lives. That is the reason why a Flat Tax is so unlikely to happen.
As to the specific argument Adams makes, I'll restate as:
a. Government knows everything, and I don't care, because it doesn't harm me directly and it might do some good
b. Paying taxes is a burden, but it's probably worth it
c. Taxes are high, but it's probably worth it
d. Given a., b. should not be true: government should do my taxes for me
However, I submit that if d., then a. wouldn't hold true any longer. That is: if government were capable of actually pulling together all of this information about you, then government would be much more likely to cause you harm by its knowledge of you. Government doesn't harm us directly with all this "spying" on us because it is only looking for terrorists (generally speaking, and broadly defined). If it was looking for all of your activity that it wanted to micromanage, it'd be far more capable of harm.
Now, I stated disagreement with b., because the burden is not there out of necessity of the revenues; and I of course don't agree with c. either, because I believe government should be much smaller. But those are orthogonal to my point about Adams' point.