1099NEC and IRA Deductions

I have two questions concerning income documented on a 1099-NEC and IRA deductions

1) If the income reported on a 1099NEC is from a "sporadic source", and that uncommon situation is checked in TT, is that money not considered income and therefore you can not take a deduction for a Traditional IRA contribution?

2) The only income received is from a 1099NEC of $5931 and is reported as self employed in TT.  TT walks you thru completing Schedule C and making a Traditional IRA contribution.  The end result is Federal Deductions are greater than the income, so that the taxable income is 0.  Yet TT still indicates that a tax of $837 is due.  This tax does not change regardless of whether I record and IRA contribution or not.  How is it that you can have a taxable income of $0 and still owe tax?  And, if TT indicates that an IRA deduction is permitted, why does not the amount of tax owed vary as I vary the amount of the IRA contribution?  Please see below Screenshot 2023-04-06 at 4.18.44 PM.png