Author here, I can see why you have these questions. I tried to keep the moments short so left out some details.
For the first one, it was the passive aggressive tone and the fact that it was posted in a public channel. This person in one other occasion, stormed out of a meeting room whilst another colleague was trying to explain something.
For the second one, later on through mutual colleagues I realised that he essentially thought very little of me because at the time I was a junior developer so I made lots of mistakes in my code base. In my defence though, I was on my own and I had to learn Rails myself.
For the third one, I put the "non-technical" part in to indicate that my manager does not have the technical capability to determine whether my findings were biased. It was more so that he had his agenda and just wanted me to confirm his approach from the technical perspective.
Hope that clears things up a little bit. :)