It's because we don't have a strict distinction between worker, technician, engineer, architect. People tend to assume all kind of roles, informally. There are also lots of flat hierarchies, with everyone contributing to decisions. Sometimes the job is just shitting out a few lines of Javascript/ruby/whatever, there's no need to know about theorical stuff.

Another thing is that since you have almost all the necessary info online, and that open source is a very big thing, there is way less gatekeeping compared to other industries.