It's equally possible there was one engineer with some free time who thought it would be cool.
Implementing a watermark isn't a thing anyone thinks is a cool feature they want to try out.
It's probably silly to make OP's judgement of any of these implementations in isolation, but you can sense a real fear about the growth (or lack thereof) inside Bluesky. Fiddling with the presented metrics (likes count getting moved ahead of reposts), promoting total user signups while being silent on collapsing DAUs. They are promising a lot at once with AI custom feeds from Attie and subreddit-style communities that smells like feature creep.
Adding a watermark, how radical, dude
And such engineer would have enough organizational clout to just ship it without going through anyone?
This is correct. I was tired of Bluesky screenshots looking bland, no culture of fear needed