Cares Act Section 2302

Why did Turbotax automatically select to defer the employer's share of the Social Security tax for my self employment taxes? I use Turbotax as a tax preparation tool and trusted that I would be guided through the process. I never would have opted to defer a payment that would come due at a later date. Today I received a notice from the IRS stating that half of my deferral payment will be due by December 31, 2021.