I like to think of such "strange" highly voted posts as revealing a hidden correlation. Yes, there may not be any obvious prior reason to expect that people who frequent HN find David Bowie or his death significant. And yet they do. There doesn't have to be a cause-and-effect or "logical" explanation. It is what it is.
People who frequent HN are likely to be part of the set of people who have been influenced by popular culture, which is a superset of David Bowie fans.
This would imply that all/most posts about popular culture figures are highly upvoted in HN but I doubt this is the case (no data, just subjective impression).
I think it just implies that HN users are informed by popular culture. Not every cultural figure is likely to be as important to HN users as every other, but some[0] clearly are, and posts about deaths are of a different sort.
