I received a 5071C letter from the IRS and want to know why Turbotax was not able to provide adequate verification to the IRS so I don't have to deal with this situation?

[Opus 17]

Turbotax has nothing to do with how or why the IRS selects certain returns for verification.  They may be looking at many factors, their methods are secret.  We have a good idea that returns may be selected if you had an address change; if you are requesting a large refund on a debit card; if your bank account for direct deposit changed; or if your employer did not submit the employer copy of your W-2 to the IRS.  There may be other reasons that are not disclosed.  The whole point is to protect you from identity theft.  

https://www.irs.gov/individuals/understanding-your-5071c-letter