But if you're filling a RoR web development position does it matter?
Yes, it most certainly does. In the long run, the developer with the better grasp of fundamentals (e.g., discrete maths, data structures, algorithms and so on) will produce better code. NB, I'm not saying that the "naive" web coder can't produce good code. Nor am I implying that CS education always makes you a better developer. On average, however, that's exactly the case.
The fact that people with a CS education are better coders does not imply that the CS education made them better coders. Without more evidence it's just as likely that people who are, or will become, good coders anyways tend to get CS educations. Do you have any evidence besides correlation that a CS education makes you a better web developer?
I guess you're either asking one of two questions, both which seem strange:
1) Do you receive magic fairy dust during college that makes you more productive and removes bugs from your code? No, I don't think so.
2) Will someone who knows the things taught in a typical 4-year undergraduate CS education be a better web developer? Obviously (?) yes; you can look at any of them and clearly see that they are good things to know. Will you point to some particular thing that you think is useless? Let me list some that seem reasonable for a lot of web development: non-trivial data structures, for understanding databases; experience with multiple languages; continuation-passing style; general system and network architecture (e.g. the OSI model) -- and so on.
I wasn't arguing that CS fundamentals wouldn't make you a better developer. I was just asking for better evidence than a mere assertion, which you provided by citing specific examples. So, thanks, that's informative.
You'd be surprised at how often a cleverly chosen data structure or algorithm can improve a web app. For instance, where I work our frontend code uses tries, heaps, and other data structures (and using these makes the user experience noticeably and measurably better than using slower data structures).
