Nah my dude, back when techno was seemingly more popular, like in the mid 2000s to mid 2010s or so, all the actual techno nerds that enjoyed the music, created their own techno in Fruity Loops, and/or loved playing DDR (Dance Dance Revolution), would all make this sound when discussing their music interests and works (and game scores).
It wasn't a mockery, the verbal sound literally came from the techno/raver scene. They were often fucked up on MDMA, LSD, and who the hell knows whatever else, for them it's all a fun sensory overload...
Thank goodness I haven't heard the 'untz' sound verbally emitted in over a decade, but I bet there are still some techno fans that still do it.