@narcell native dark window manager stuff like topbars, buttons, dropdowns etc. being reflected was disabled because it created too much inconsistency. So dark mode as a whole was removed.
here's the commit: https://github.com/pure-data/pure-data/commit/1665a2ef341413f036251dfb88136223ca1fbf2c
(from the comment it seems like it's set to true in 2 places, the defaults file as well as the plist?)
though I'm successfully reading from some defaults to tell if darkmode is on here... idk