Steampunk is a creative way of looking at technology. The idea of good steampunk (IMO)is to mimick modern technology using classic methods - for example, using steam power instead of electricity.
It's worth noting that the whole 'steam power' thing isn't a requirement. Steampunk can just refer to a classic style of design applied to modern technology, like this http://gizmodo.com/assets/resources/2007/02/steampunkkey.jpg
Like an school of design, steampunk isn't for everyone. Not everyone likes surrealism or expressionism, but they have their fans. Steampunk is no different.
Also, regarding the 'obnoxious' steampunk fans, there are a lot of pretentious wankers out there that think their favourite thing should be yours too. Don't let them put you off something, decide you don't like it based on the merits (or lack there-of) of the concept