He didn’t say what his skills were and he didn’t say the organization he worked for.
Yet you read that small sentence from him and from that surmised that he was arrogant and incompetent, all from a few non-descript words!
It’s like someone saying “yeah, I learned take-down skills in the Army” and you replying “you obviously were a remf who never went anywhere near combat. POGs like you always brag about non-essential skills like typing and filing papers alphabetically.”
Wow. You are kind of worked up over this.
If you want to know more detail, it wasn’t about the poster at all - just the words reminded me of these two people I know that I used to work with that were not very good technically, yet they always thought doing a few things with Salesforce made them the most valuable people in the world. Our company improved when we finally got rid of them.