For normal operations the pilot doing their own check isn’t a lack of confidence in the ground crew, it’s the prudent, smart, and responsible thing to do when playing with people’s lives and very expensive aircraft. I’ve never known ground crew to get upset over it.
(Which means I’m only partially right, but I admit mostly wrong. I’ve also seen strong evidence that the Blue Angels do something similar, but can’t quickly find a reference.)
I don’t really understand why they do it, to be honest. Most other military display teams, including the famous Red Arrows and Frecce Tricolori, just do regular startups with all the usual preflight checks.
The people who go tend to be the ones everyone hates at the front line squadrons because they are the sticklers for doing things right and putting in the work to do it right AND fast. Most others will cut corners on one or the other without oversight.
These are mostly war machines that have to be scrambled asap, meaning the pilot is expected to jump in and fly. To alter that during peacetime would be silly, as you want to establish habits.
But don’t take my word for it, here’s a video I found as literally the first result when googling for it, showing a USAF F-22 pilot conducting a full pre-flight walk around inspection: https://www.dvidshub.net/video/149526/f-22-walk-around
Before saying something is the ‘stupidest thing’ you’ve ever heard, it might be worth first making sure you actually know what you’re talking about.
There are no shortage of horror stories about what is found when USAF pilots get deployed to train pilots in other Air Forces.
The USAF is also not any more professional than other developed world and NATO air forces, who all have similar procedures in any case.