I would strongly disagree with that.
You can't defend against something you don't understand.
You definitely shouldn't spend time learning some script-kiddie tool, that is pointless. You should understand how exploits work from first principles. The principles mostly won't change or at least not very fast, and you need to understand how they work to make systems resistant to them.
One of the worst ideas in computer security in my mind is cargo culting - where people just mindlessly repeat practises thinking it will improve security. Sometimes they don't work because they have been taken out of their original context. Other times they never made sense in the first place. Understanding how exploits work stops this.
I've seen an increase in attempts to trust the client lately, from mobile apps demanding proof the OS is unmodified to Google's recent attempt to add similar DRM to the web. If your network security model relies on trusting client software, it is broken.