Sometimes I, as a Rails developer, forget which is supposed to be pluralized, the model or the table. (Gah!)
Still, Rails' pluralization algorithm is savvy enough to know when it can't just add an 's'. Most of the time, it works.
If you don't like it -- like most things in Rails -- you can just turn it off with one option.
It's the fact that you're allowed to dislike features like that, and make them go away, that makes me wonder how people can hate on it. It's opinionated, but it's not dogmatic.
Hell, it doesn't even completely work in English, either. Not all English words are pluralised simply by adding a trailing 's'.