The host provides the theory that the vote is not biased based on left or right wing beliefs.
If new users are not taught by existing users what the existing users like and think should be upvoted, then what is upvoted will naturally shift over time.
Long-time members may consider that a deterioration in "quality". Quality is of course subjective, but I suspect in this case it actually means more like "not as close in alignment to the way things used to be, which I liked".
I'm fairly new here, and as a newbie, I haven't ever been taught what the existing community thinks I should upvote, whether in submissions or comments. Beyond the guidelines, which state:
> Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.[1]