I've underpaid precisely once, when I didn't know about qurterly reporting, and the so-called "penalty" was nothing unfair -- just the interest the money earned in my account instead of the IRS's.
The IRS already knows the numbers on W-2 forms because they get the same data from employers. Financial institutions also send them 1099s and other forms.
So the IRS already knows all the numbers. There's little point in making people manually re-enter the data.
The IRS should automatically fill in everything it knows about, and then let people add deductions and unreported income if they need to. It would make filing taxes almost a no-op for a lot of people.
The one time I underpayed I promptly received official letters from the federal and state governments giving me time to pay them with a very minor penalty (it was well under 1% due to the short time frame). It was simple and easy.
Ironically the Trump tax cuts made this even easier as the standard deduction was doubled making it much less attractive to itemize.
The ask is for the government to declare what it knows about a resident's taxes upfront, and then letting the tax-payer decide how much they want to invest in contesting the government's calculation. The conjecture is that for most people the need for contesting the government's math will not be needed. Currently, the part you call "responsibility" results in tax payers paying a third party millions of dollars every year. The expectation is that this waste of money can be largely avoided. How is that whining?