I absolutely share your intimidation by really outdoorsy-oriented profiles. It makes me feel like the person would always want to be off doing things I didn't know how to do, wasn't fit enough for, or just wasn't interested in.

You describe it well - I get tired just reading this stuff :)

Bicycling as a primary mode of transportation is common among people my age in my city.

I see - fundamental attribution error again. The true explanation is more situational than dispositional.