The NASA paper does not say that Sandy was not influenced by climate change. What they actually calculate is that Sandy-like hurricanes occur once in 700 years under pre-industrial conditions. Here is one of many relevant quotes:
The fact that our calculations show Sandy’s track to be so rare under long-term average climate conditions lends support to a climate-change influence. On the other hand, the most recent climate model simulations project reductions in blocking frequency in a warmer climate [Dunn-Sigouin and Son, 2012]. Global high-resolution models suggest that tropical cyclone frequency will decrease globally, while mean intensity will increase. There is growing consensus that the most intense events will increase in frequency, but there is high uncertainty, especially in individual basins [Knutson et al., 2010]. On the other hand, further sea level rise is almost certain, with a meter or more expected in the next century [Nicholls and Cazenave, 2010]. This will exacerbate TC-induced flooding even if the storms themselves do not change.
Someone should have RTFA.