I'm not sure if you were assuming everyone should recognize his name. Because, without that context, it is clear there are many many people, every day, who suffer things that many of us have sympathy for, but would not make a lot of sense to probably anyone to alter HN, every day, in sympathy for.
If you're the kind of person who prefers fairness over indulging feels, then token efforts like pinning ribbons to things look like an ostentatious display of hypocrisy to friends and family, to show that you care about something everyone still collectively agrees not to do anything about (i.e. a kid dying).
You can make an argument that HN must be 100 percent on-topic, at all times, and that it doesn't belong here. But you can also argue that we are all humans and we can just accept it once in a while, even here.
To jump to the conclusion that it's all just for show, and nobody will actually take any sort of real action is pure cynicism. People have actually been affected by this, in ways that are certainly small in comparison to the the way the Meyer family has been. The most visible gestures might not accomplish much, but many people are actually donating money to charities that have a very real impact.
The thoughts it raises, particularly for parents, are not the kind that can just be dismissed once the hashtag stops trending.
I think almost everybody understands human loss and can empathize. It's a bit rude to assume that someone doesn't, just because they don't want to support this rather tasteless memorial.
A child's life ended and now there is a color named after her (or some site changed a color band). What exactly is that doing for anyone other than adding a bit of trivia to the CSS spec so that people can read about it and say "Oh, that's horrible!" and then move on with their lives? What is that doing for the parents? Is the perception of this named color supposed to invoke some kind of warm feeling? Is it to let the parents know that "we support you"? If so - don't you think providing some actual support in the form of something useful would be much better?
Now pay attention to this next part because it might be hard to follow. As humans, many of us empathize with this profound loss experienced by someone whose work has been so influential in our own careers. As humans, many of us have experienced similar loss. Many more of us, as parents, hope never to have to.
If that's unclear, perhaps someone who is a better programmer than I can translate it into code and put it in a Gist.