Why am I required to pay my intuit fee using my debit card when I elect to pay with my refund?

If the IRS is taking too long to send your refund they will ask you to pay the fees, see step 3 under What happens if the IRS reduces my refund......
https://ttlc.intuit.com/community/payments/help/what-if-my-federal-refund-isn-t-enough-to-cover-my-turbotax-fees/00/26313

If you don't pay they will automatically debit your bank account. Then when the IRS does send your refund they won't take the fees out again And, Why you got charged,
https://ttlc.intuit.com/community/charges-and-fees/help/why-was-my-bank-account-auto-debited-for-turbotax-fees/00/26102

Turbo Tax says......

We understand that these are unprecedented times and we’re committed to helping our customers who are experiencing hardships. If you’re in need of assistance, call us by the Tuesday prior to your debit date at 1-888-808-1723 to speak with a trained specialist and mention “auto-debit”, or visit TurboTax Support.