To be fair: The criteria is the worst you've played. Which means popular ones are more likely to appear, because fewer people play the less popular one.
If you haven't played it, you can't really suggest it. S'why, while I'm convinced my suggestion is quite possibly the most diabolical in the thread, it's very obscure and it's understandable that few other people have encountered it.
Yeah, there's no point in wondering why people occasionally list the Star Ocean, Tales or Final Fantasy games when outside of Japan they are probably the series people think of, due to being popular and having multiple games. The odds are in their favour for an entry popping up as someone's least favourite. As proven by this thread, there are shedloads of awful JRPGs that have probably only been played by a handful of the posters in this thread purely because they are awful, obscure, never made it out of Japan or all three. Personally I'm sure Dragoneer's Aria is a worse game than FFXIII but one of them sold several million copies and the other didn't.
The Dragon Quest games virtually never get mentioned in these threads though, I suspect because they tend to be quietly restrained with the storylines and characters, and don't toy with the mechanics as much either.