bash is a shell, it's even in the name: 'Bourne Again Shell'.

But bash is also a programming language. I couldn't find the talk that you're referring to, but Joe might have been referring to

1. 'using the shell' - as in, interacting with your OS through text, learning POSIX commands (which you could be executing with bash) and the mindset you need for shell usage

2. 'using bash' - as in, using bash as a scripting language

also vim > emacs ;)