Why did turbotax let me claim standard deduction when I am a dependent?

[VolvoGirl]

Everybody gets the Standard Deduction.

The Standard Deduction for an individual for whom an exemption can be claimed on another person's tax return is limited to the greater of:

…..$1,250 or

…..Your earned income for the year + $400 (but not more than 13,850))

So you would get a minimum of $1,250.

See Table 8 Standard Deduction worksheet for Dependents on Page 26

https://www.irs.gov/pub/irs-pdf/p501.pdf