I don't have a problem with people bragging about a thing they made. I think if someone spent a bunch of time on a thing, I'll give them time to be proud of the work they did and give them space to show off.
if it's something I'm interested in. The difference between "ShowHN: I built a thing", and "ShowHN: thing" seems inconsequential to me.
But you know that one about how naming things is an unsolved problem in computer science? Looking at random search results, I think it's more about it being a more natural way to describe something. "Show HN: I built a thing that does blah", rather than "Show HN: Foobar, a thing that does blah".
If I do "Show hn: George", what's George? vs "Show HN: I made a thing that does foo called George"
Interestingly enough, there are only 805 results for "Show HN: We" vs 5,060 results for "Show HN: I", What a bunch of loners we are.