I came up through sysadmin, networking, infrastructure type work. I always assumed that programmers knew everything I knew PLUS how to write programs.

First project where I spent any appreciable amount of time with programmers was eye opening. I was perplexed that not a single one of them had ever run a network sniffer or strace or had the faintest clue about HTTP or how browsers maintained state with their application. I squatted in a room with them for 4-5 weeks and acted a bit like an xray machine for any problems they were encountering. I didn't know anything about programming, so they would tell me what the code was supposed to do and I would show them what was actually happening on the wire or filesystem or whatever. It was a lot of fun and we all left the exercise having learned a lot more than expected. This was nearly 20 years ago, tooling has improved a good bit since then but it still helps to be able to get into the weeds.