I have met Ken (around the time that YC received an original Xerox Alto and he was one of the experts who got it working again). Ken may be the least smartass person I have ever met.
I think you (and of course I don't just mean you, but anyone commenting here) should be more careful about publicly labeling other human beings.
I, for one, think that is pretty clear from the fact that I don't call the author by their first name. I did not write "Ken you're a smartass." Also, I did not write on his LinkedIn profile, I commented on a specific article.
In any case, it is but one of many comments and by up-/down voting, the community can send a signal to the author (if he reads here) as to whether he appears to be a smartass in this article. I think that is helpful.
I hear you that your intent was good! but that, alas, is not enough; a comment like that snaps to an ugly internet grid even though you didn't mean it to.
I don't think it's safe to assume that readers would understand that you weren't passing a judgment on the author. You called him a smartass.
I agree that, not having met Ken, you couldn't know how inaccurate and unfair that was, but you shouldn't have posted it in the first place. It's clearly against HN's guidelines: https://news.ycombinator.com/newsguidelines.html.