Hahaha...It's not a must we make a thread about our first Bitcoin on BTCt unless we want to show off or attract attention for merits. In my cryptocurrency journey so far, what've learned that is also crucial to Bitcoin itself is privacy, even if you do not want to anonymize it, privacy is important. For instance, this is the way I view it, if I deposited $500 in my newly opened bank account, why should I be broadcasting it? If others will show off, I don't think it is wise for security and privacy concerns. So not doing it at that time even saved you as far as I am concerned because the less people know about you, the better when it comes to money.
I agree with you on what you said but some people don't really know how to keep such achievement to themselves and I believe that since nobody knows who is who on this Forum just username, that's why the OP decided to make it look like a public announcement which it is.
Fine is good to share good news but the way we take it sometimes is not how is suppose to be.
To be frank with you, I too would like to get my first BTC and start up something as the OP did, is everyone's dream especially those who are new in Bitcointalk to get their first BTC but not everyone would make a public announcement about it, safety first.