Before subtractions my total deductions were 19k including mortgage interest. After subtractions this went down by 11k. The author is lying, obscuring the truth or hiding something.
There is a factual problem for sure. My mortgage is much smaller than 313K, yet the difference for my family of four between the standard deduction and the itemized this year was about 12k or almost 4k in taxes. Perhaps the poster is advocating using the standard deduction along with the other itemized deductions except for mortgage interest?