From what I read that seems plausible given the pilot was a seasoned test pilot; so it seems odd he was just being panicky.

Imagine just being struck by lightning, loosing main displays, and being at 1200 feet. All on top of flying in a plane with a reputation for electronic failures.

I'd be concerned too that the plane was about to freak out. 1200 ft isn't far.

2000 hours isn't all that seasoned, and he had less than 50 hours in that type. He was accomplished all right, but not what one would call seasoned.

In fact, the root of the word "seasoned" means "prepared" and he clearly was not prepared for the events leading to this incident. That through no fault of his own, hence he was not formally disciplined.

The Marines expect someone of his position to perform above and beyond their training. He didn't, so he lost that position with no formal discipline.

Why are people in other threads saying that he was some sort of expert or that he lost an expert position because of this?

This.