Why am I being forced to upgrade to Deluxe to include my student loan interest? I did not have to do this in the past. I will chose another vendor if this is the case.

Because TurboTax has made changes in compliance with the recent IRS tax law changes and updates.  Sounds like, very likely your situation in 2020 is not supported by the tax forms in the TurboTax Free Edition.  In addition to the TCJA, TurboTax is re-coded or programmed so to be incorporated with the New CARES act and SECURE act due to Covid, you might need to use new tax forms to claim the same deductions, credits, or forms of income like the student loan interest deduction.  Some of the situations have been transformed into TurboTax Deluxe and TurboTax Live Deluxe, instead of in Free Edition. 

You have another option.  You can use another free program.  It is an IRS Free File Program delivered by TurboTax which is exclusively available online and has its own dedicated website at taxfreedom.com.  It isn't accessible from the "regular" TurboTax.com website and is not the same as the TurboTax Free Edition.  For 2020, the eligibility requirement for the AGI  has increased to $39,000.

Hope it helps.