I don't think anyone needs more evidence that Trump is a crook; I think the concern is that Trump is enough in cahoots with for-real foreign adversaries who are at odds with FISA-authorized surveillance (as it makes real operational problems for them), and they might be telling him how badly he needs to kill this to weaken it. He usually doesn't get anywhere deep into policy on this kind of stuff. Unless someone smarter than him is telling him what's important, he just talks about windmills and toilets and Crooked Hillary and how the election was stolen.
I honestly don't know whether it's that, or whether he's having an unexpected interest in policy details just because it came to his attention somehow and he knows the US national security apparatus is bad because it was mean to him. It could be either one.