> Why do people hate SQL?
There are two (EDIT: three, really) kinds of anti-SQL people I've encountered:
1. People (often SQL experts) who dislike SQL, or at leats prefer/propose alternatives to it, because it has features which make it less-than-elegant in dealing with some problems which are fairly straightforward to address under the mathematical set theory underpinning the relational model. [1]
2. People who, for a variety of reasons (some well-considered and valid, some less so) prefer not to use relational data stores at all. (E.g., the NoSQL movement, which, despite the name, is really about alternatives to relational-model-datastores, not alternatives to the SQL language for relational datastores.)
EDIT: And, probably most relevant to your observation that:
> whenever I mention SQL to ruby developers, I get a sense of aversion.
3. Application developers who have a strong preference for working exclusively in one preferred language, and don't really want to deal with anything outside of that.
[1] Hugh Darwen and C.J. Date are prime examples here; see, e.g., http://www.dcs.warwick.ac.uk/~hugh/TTM/HAVING-A-Blunderful-T...