DAR is a test pilot, nit picking is his job. A good test pilot is quite capable of writing a ten page report about how badly their toaster works, then to conclude that it actually works quite well. It would not occur to a bad test pilot to even analyse his toaster.
DAR is a good test pilot, with an impressive professional reputation.
We are many of us here also aerospace professionals. There is a basic mode of communication amongst aerospace professionals, it goes something like this: "you idiot, why on earth did you do that?". Fell free to go and search out the number of occasions people have said that to me on Pprune, there are a fair number.
Good aerospace professionals also have another mode which is to listen bloody hard to even the mildest comments, with massive humility, and take everything on board.
Nit-picking, again, is basically a survival strategy in aviation. The search for perfection is another, even if we all know it's a fiction.
Where you wish to sit on this spectrum, is ultimately up to you.
He was being serious about straight and level being difficult?
It's probably the easiest thing I've done.
Told me to climb/descend to XX altitude and I did it just fine, no assistance and stayed +/- 20ft of the given altitude.
Whilst doing the radio, navigating, in or close to cloud, managing the aeroplane systems, looking out, staying on track, talking to your passengers, and for potentially several hours at a time?
Just when people are trying to defend you, you really do manage to dig another hole for yourself over and over again. The people telling you, a 6 hour pre-solo student, that you don't understand, have thousands of hours, on hundreds of aeroplane types, across half the planet. Listen to them.
G