And why is it so wrong for the shell to be a decent programming language? It's not impossible. It doesn't need to make anything harder or more complicated. And it adds a ton of functionality. There are tons of people programming in Bash and powershell anyway.
Someone who tries to learn Chinese may have the same thought after having been exposed to nothing but English. The keyword is "language".
The quoting rules in bash/sh are not difficult to memorise, and definitely a must-learn.
I wanted to do floating point math.
Maths is not a strong point of shell languages because they were designed more for string manipulation and gluing other programs together. Try doing pipelines and redirection in a "real programming language", for a contrasting example.
"The right tool for the job".
You shouldn't, certainly, but, as to 'can't', I think that `expr` (or, as I just learned from ABS, `$(( ))`) covers a lot of basic uses: http://www.tldp.org/LDP/abs/html/arithexp.html .
I wanted to do floating point math. The recommended answer is to pipe your data into a better programming language. You can't even do math in bash. On another occasion I wanted to make a simple program that opens a random file. The recommended answer breaks in the simple case where files have spaces in them. The correct answer I found is this horrible mess of weird characters and it's completely incomprehensible. The best answer someone submitted was just to call one line of python from bash...