It never matters how inefficient the code anyone writes is. It is never necessary to understand the complexities of algorithms, data structures, profiling, or benchmarking. All anyone needs to do is write code as fast as possible that functions correctly. It is never important to ensure your code scales because CPUs are getting faster than everyone's data is getting larger.

I have already agreed with your sentiment and am not arguing that you are wrong. I am pointing out that what you have said may not come across as a rule of thumb to everyone. In fact, the way you have bolded it, upper cased it, and followed it with an exclamation point - you have made it seem like there is no room for discussion. If you take your argument to one possible logical conclusion, it becomes ridiculous.

"You're using Perl because it's at that sweet spot between simple and expressive

That is a bad starting assumption. Why don't you come hang out in #perl on freenode some night. There is no end to the number of people using perl (and PHP) because they do not seem to be competent enough to learn any other language. The task at hand may already be borderline at best for being done in perl. Throw in inexperience and lack of knowledge and it will never accomplish the goal - no matter how long you let the CPU spin.