[yellowapple]

You ask this as if all coding bootcamps teach these things, which I highly doubt to be the case. In fact, I'm aware of several "bootcamps" for both Java and Python. Hell, there's even one out there for COBOL: http://www.wintrac.com/courses/mfcobc.asp

As someone who ended up learning Ruby (and Rails) for a previous job, I can attest that it's a great language from a learning/teaching perspective. Huge ecosystem, the syntax is actually readable, you don't have to fiddle with compilers, and so on. As mentioned in other comments, Rails is also the archetypal MVC framework, for better or worse; while I don't personally care for it, it gets the job done and is in relatively common use; in terms of getting students from zero to hireable quickly, Rails knowledge is pretty useful.

Meanwhile, Javascript is one of those necessities for web development, for better or worse, so a web-centric bootcamp will understandably put some emphasis on learning it.