They have a HN history going back nearly a decade (pre-LLM) with comments mostly not looking like trolling to me. My first guess would be that they've just been exposed to a bad implementation of Pair Programming and TDD (or even a "good" implementation in an environment where it's not a good fit), and that's where they developed those opinions.

TDD especially has a lot of critics. Some of that's justified. Some of it is just a difference in thought methodologies (e.g., a fraction of developers "think" through a problem by writing code, and the "tests" mandated by TDD physically can't meaningfully appear till after some implementation has happened). If a rando developer thinks negatively of it, that's not news to me. If they haven't tried it much and misattribute the exact cause of those negative opinions to be able to form a nice story-centric through-line, that's also not surprising. I'd be much more inclined to believe they're a developer who you disagree with than a deliberate troll. Who knows.