I guess it all depends on specific examples, your question is so broad that seems almost unserious. The "speculative and crazy ideas" is unqualified, so there's a very strong possibility that (1) they're simply unhinged or idiotic or (2) they don't make sufficient business sense to be supported by anyone, regardless of whether those people are "founders" (whatever that means) or employees.

It's also a matter of statistics at play; HN is a social media platform - as opposed to a founders-only platform, and employees make for a significantly larger pool. It would make sense to see that kind of difference in numbers.