Piyush Goel should have just stated that the the Mod will respond to requests for proof, at an appropriate time and if the occasions demands for it. He should have stated that he is not part of the CCS(I'm not sure he is) and hence not privy to such information.... When will our netas learn to talk in a manner appropriate to their public stature and
Logically speaking he couldn't have done any different!
It's election season, Congress & co are afraid that Modi will tom-tom the air strikes (as is widely acknowledged that he's the only one who's had the guts to order such a strike) and steal the elections! So opposition is trying to poke holes in Modi's narrative!
A journalist asking a similar line of questions (as Congress etc) quoting unfriendly non-Indian news papers would obviously entail the same response as campaign trail. If he was any conciliatory then that would embolden the opposition's line of attack.
Net-net, Piyush Goyal's performance is bad optics for limited setting of an intellectual discourse, but is commendable for 'message consistency' - all hallmark for winning elections.