Some of us actually did know him. I did, albeit not as well as others here, and I see no harm and much good in people celebrating his accomplishments in his chosen career.

You don't necessarily need to know someone personally to feel a sense of loss. You can feel a "bond" with with someone based on all sorts of things: being members of a common community, sharing a common occupation, etc., etc.

To illustrate one case that hits close to home for me... when I think about the 343 firefighters who were killed on 9/11, I find it difficult not to tear up at times. Even though I never met any of them, and couldn't tell you any of their names. But we shared a common bond, by virtue of being firefighters. My sense of loss at their death is rooted in how deeply I admire all of them for the bravery and courage they displayed on that day, putting their lives on the line in the name of saving others. Do I feel that as strongly as if I had been the literal biological sibling of one them? Possibly not, but they were still my brothers, and the sense of loss is still real.

Without piling on: sometimes this is how you get to know someone.

It used to be interesting to scan the obit section of newspapers, just to see the parade of characters and achievements that I had missed or not known enough of.