I had a job interview and didn’t do well on the technical part (got nervous). Never heard back, even after a follow up. I was really surprised because they seemed really nice overall. I wasn’t even expecting an offer, just wanted to end things on a friendly note. I thought it was unnecessarily rude.
If you haven't gotten your answer, then you've gotten your answer. Fill in the likely blanks: they are busy with their day jobs and as you admit, they're assuming you already know the outcome because you bombed the technical assessment.
I get that no answer is an answer, but OPs post was about people being rude and this was an example of that. "busy with their day jobs" is not a good excuse for not sending an email that takes 30 seconds.