* none of those events in play => -1 Funding;
* only Pirates in play => cancels the normal decreasing (-1+1=0, i.e., no changes);
* only Fracking in play => an additional -1 Funding;
* both in play => Funding decreases only by 1.
The gist of my interpretation: do a simple sum.
I am inclined to agree, but the wording on the card itself is a bit unclear. If your interpretation is correct, perhaps in a reprint the Pirates card could read, "After resolving the end-of-turn Funding drop (including Fracking, if in play), +1 Funding."