As much as air palm or jyuuken is suggested to obliterate Susanoo, I too am weirded out that it is possible. maybe because of how the series showed how formidable and indestructible Susanoo was. but also, the likes of Tsunade was able to hold her ground against Madara and crushed a part of his Susanoo using her sheer strength.
We were conditioned to see Susanoo as something indestructible that even the potential of it being destroyed by a technique by a Hyuuga, or someone who is relatively underdeveloped, is considered farfetched, a forceful wank.