You know what you're talking about, so I'll agree that you're right, but the simple action of searching titles of submissions on Reddit didn't work. That makes it seem like that there's something wrong with their code or database setup. Reddit's source code is pretty disgusting.
Their problem, as I see it, was mainly that they were using Solr, which requires an inordinate amount of time to configure and maintain (time they didn't have), and also isn't good at handling frequent updates, like the up and down votes.
I don't think it's a bad sign at all. Good search is HARD, and plenty of companies outsource it.
This said from someone who was part of a search startup acquired specifically to power a larger site that couldn't do a good job themselves.