That's not fully true. There is also a contingent of people who like to use the the tax code as a mechanism of policy apart from efficient collection of revenue.
Tax credits for education, clean energy, penalties, small businesses, mortage interest, each one of those one-off changes adds complexity, and in total ultimately can make the process dramatically more difficult.
While all of this is true, other countries have a system where the government tells you what tax they believe you owe, and provide the details of how they reached this number.
The citizen can either pay that number, or offer amendments to the details which imply a lower rate (or higher if you're a masochist, I suppose).
That's independent of the complexity of how that number is derived, and in balance I would rather the US (as a citizen thereof) use this sort of system than the one we happen to have.
One thing to add: You're typically still obligated to file a return if the prepared taxes are not correct. You're not "off the hook" in any way by accepting what the prepared statement says. This mostly bites e.g. entrepreneurs with more complicated taxes, especially if you filed for an extension on the business side.
> There is also a contingent of people who like to use the the tax code as a mechanism of policy apart from efficient collection of revenue.
There is nothing inherently wrong with that. Whether you do or do not agree is a different question.
It's interesting to look at different cultures:
The Swedish word for "tax" is "skatt", which literally means "treasure". Historically it was part of the treasure to be collected by the monarch and other people in power. So, not really a way to cover government expenses, but for somebody in power to enrich themselves further. Luckily, the country has moved on from that, just kept the word (and the king).
The German word for "tax" is "steuer", which literally means "to steer". That makes it clear that those fees are not just collected to finance government expenses but to even steer society in a certain direction, i.e., what you mean with policy.
In the US that's mostly because that's the biggest lever the Federal government has to pull. The power to legislate things within states directly is mostly devolved to the states so Congress mostly has the tax code to point a firehose of money to incentivize things. It's why the Affordable Care Act hinged on the individual mandate initially, all the regulation of healthcare legally depended on the existence of a tax to put it in Congress's legal authority.
Tax credits for education, clean energy, penalties, small businesses, mortage interest, each one of those one-off changes adds complexity, and in total ultimately can make the process dramatically more difficult.