The only reason that charitable deductions are flow through items on the K-1 is so that the AGI limit can be applied at the individual level.  But for that, it would just be a normal business expense and reflected in a reduction of box 1 income on the K-1.  Doesn't that mean that it is "a deduction . . .with respect to any trade or business of the taxpayer" (Reg. 1.199A3(b)(1))?