I really don't like the hate for perl. Sure, it's got some stuff which can be a bit difficult to understand at first, but that flexibility is nice when you just want to whip something up quickly. It reminds me of how people love to hate Java because of it's verbose code (myself included). At the end of the day, if you know what you're doing it really doesn't get in your way.

I do a lot of metaprogramming and text processing at my job. Using regex as much as I need to in most other languages just feels clumsy compared to perl. It's a great language for sysadmin type stuff. It has a good niche. I wouldn't use it for what this guy did, but I have no doubt that tons of stuff in CPAN probably made his job significantly easier.

I don't think perl is hard to learn - I spent a few days with the camel book and was able to pick it up fairly quickly - and as others have said any language can be unreadable or abused. Also, I don't use Moose or objects in perl and I think that OOP can be cool but can also be abused just as much as perl's nonstandard syntax.

When it comes to other types of projects, I don't think your language of choice makes a huge difference in theory. I think javascript, perl, python are all pretty good and not too hard to pick up if you already have programming experience (don't know about ruby, although I assume that the same holds true). What really makes a difference in practice is the network effects, though. I really love perl, but I'm going to go out of my way to learn other languages because no one respects it and the job market isn't as good for it. Oh well. I don't really mind having to choose based on fads because I honestly think that my choice of programming languages won't make much of a difference on my performance.