As Relache said, it's because a lot of us write pointless questions and forum posts just for the sake of "shinies". Don't worry, I'm not trying to imply anything here.
Furthermore, others feel like the Hubber in question is showing off and it fills up their feed with annoying announcements. They don't really do anything or prove much, seeing as most are just out of totals. I can understand if it was something like getting "Hub of the Day" or the "HubNugget" accolades, but other than that, there's not really much to boast about.
So TL;DR, some people just think it's boastful. But me? I like seeing what people have earned - you don't learn a lot about the Hubber, but it's something ^^