I think it's far more interesting to ask how a thing might work, which uses cases might be dramatically underserved today and serve as a beachhead, or the tradeoffs being made rather than just say something is a "bad idea."
Dropbox launch: https://news.ycombinator.com/item?id=8863
Coinbase launch: https://news.ycombinator.com/item?id=4703443
A 2012 thread discussing comment negativity where, coincidentally, the top comment is from @iamwil who posted this link and is on the DIRT team: https://news.ycombinator.com/item?id=4363717
A classic thread from 2012 where PG talks about negative comments: https://news.ycombinator.com/item?id=4396747
To me, the most interesting ideas in the world are the ones that at first blush look like they can't possibly work. But upon thinking through how they might, you learn something.
Props to everyone in the thread who is asking genuine questions and actually trying to understand what the team is building.