I keep hearing this exact same idea and it puzzles me a great deal. Is it a computer science thing? I'm doing a PhD in signal processing / engineering and people seem to care a lot about giving simple and clear explanations so I don't really relate!

In my experience in neuroscience it even differs widely across programs/universities. Some good professors care about giving good talks, and if you're lucky it becomes contagious in the program. Others think less of you if it's clear, some are too naive to realize obscurity is not a virtue.

That's professional deformation, because signals are supposed to be clear and easily identifiable among noise.

I think there was a study at some point which showed that the worse the university, the more jargon the researchers use in their papers.