No. It's not the most important or required, but you should know at least one programming language, be it Perl, C, Python, or whatever else. The point is, you should be able to quickly write and read code so you can modify exploits, write your own tools, etc. Python is just recommended because it's easy to learn, and you can write some powerful scripts relatively quickly.
I already know some program languages, like java & c. However i'll focus myself on python. I started to read this book just to learn something about scripting languages, and then take on of them and start to learn it in the depth.
I just hope to learn something about these languages, during the master security & privacy degree that im going to attend for the next 2 years