Does this mean Reddit is a more auspicious environment for new ideas to flourish? HN is way too confined of a place for "foolishness", that Asimov sees as conductive, to be permitted without things going haywire.
One of the (potentially) negative sides of the same phenomenon is the acceptance of and tendency towards memes. They can certainly be annoying, but a strong flow of memes is indicative of a lot of culture and ideas bashing up against each other until some of the bits stick together in a novel way.
A cleverly applied meme comment on a Reddit thread can easily get hundreds or thousands of upvotes. Front page HN threads don't even get any meme comments, because people here know that their comment would be buried immediately, if not outright deleted (I admit to being much less familiar with the inner workings of HN than Reddit). Reddit threads are definitely a place of quantity over quality, but the sheer volume of creativity swirling around is bound to uncover a couple gems.
All of that said, I've never viewed HN as a place for ideas to be generated. This is a fantastic whetstone with some brilliant minds, but it can also be merciless.