That's not what the comment said. It has been unfairly misconstrued.
What BrandonM actually said was that he had "a few qualms" about Dropbox's YC application (which is what the word "app" meant back then) - i.e. he was worried on their behalf and wanted it to succeed. He was clearly intending to be helpful. He had a nice exchange with Drew, as anyone can see if they would read the replies (https://news.ycombinator.com/item?id=9224).
In 2007, the conventional wisdom was that file sync was a solution-in-search-of-a-problem that would never be a successful business because the idea only appealed to technical users. Joel Spolsky famously wrote a blog post mocking technical people who wanted to work on file sync. That's the context in which the comment was posted.
That turned out to be totally wrong, but it took the success of Dropbox for everyone to know that (and then forget that anybody ever said otherwise). Brandon's comment ended up getting stranded like a little island in an ocean of hindsight fallacy.
It's hopeless, of course, to fight the internet once it has decided on a meme. But it bugs me when unfairness get repeated, especially when someone is being scapegoated, so even though it's hopeless, I still post about it from time to time.
https://news.ycombinator.com/item?id=28293146
https://news.ycombinator.com/item?id=27068148
While I like the meme, this is the first time I've heard the context, so I appreciate that you wrote this.