The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.
This case did not involve the income tax.
It does involve the income tax, but that's not the part of the 16th that's most important here.
without apportionment among the several States, and without regard to any census or enumeration.
THAT's the part that's dangerous. It gives congress a free hand to levy any income tax using whatever criteria they wish.
Take away the second part of the amendment and congress would be force to deal fairly with everyone. They couldn't pick and choose who to help and who to punish with a larger tax.