My reading of this page shows that this only applies to really wealthy people. You had to have been paying over $160K in income taxes every year before you left, or have a net worth of over $2M. Of course, if your net worth is a whopping $100K plus some worthless artwork that the IRS says is worth $50M, you might have a problem...
https://www.irs.gov/individuals/international-taxpayers/expa...
North Korea isn't the only state that makes it hard for citizens to leave....