Democrat legislators now proposing a 15% minimum tax on corporate "book income" rather than taxable income are hoping to combine two very different taxes with different definitions of income.
Big corporations sometimes pay no corporate income tax in some years. Politicians agitate about, whipping up public outrage to help them add some other tax, because most people never took a course in basic accounting, or they slept through it.
Look at your own tax return and you will see big differences between Adjusted Gross Income (AGI) and Taxable Income. If some politician proposed to add a new 15% tax on your AGI, in addition to the regular levy on Taxable Income, that might not sound so "fair." It might just sound like they're criticizing and ignoring their own rules - the ones they put into the tax law.
The only reason a seemingly profitable business can owe no tax is because it has no taxable income. After all, income is the difference between revenue and costs. And there are many business costs that might reduce taxable income to zero or less. Some costs are spread out over time, such as depreciation of a new factory, or costs that could not be deducted in a bad year because the firm had no income from which to deduct extra expenses.