I remember seeing the same kind of arguments about Ruby when it began to become popular. "Ruby is too dynamic. You shouldn't use it on large-scale projects."
Learning a language involves more than just learning syntax and semantics. You also need to learn how to write for maintainability. It sounds like the author is less certain about how to do that with Lisp, but instead of seeing it as a chance to learn more he writes off the entire Lisp family as impractical.
Exactly. I think it's part of a larger learning pattern that people go through: one starts learning about a new tool, library, or approach, and at some point, realizes that it's not perfect -- there are some cons.
I guess there are several ways to respond at that point: one is to persevere, learning more and coming to a better understanding of what advantages and disadvantages are, as well as the appropriate use cases.
Another is to just give up and write a proscriptive blog post, possibly also with a biased, incomplete comparison of the new thing to an old thing.
The latter approach is extremely frustrating for several reasons: 1) often, the authors ignore or fail to grasp both the pros of the new thing as well as the cons of the old; 2) the proposed solution is to throw out the baby with the bathwater, instead of to figure out how to improve the new thing; 3) it provides fuel for others' confirmation bias.
Learning a language involves more than just learning syntax and semantics. You also need to learn how to write for maintainability. It sounds like the author is less certain about how to do that with Lisp, but instead of seeing it as a chance to learn more he writes off the entire Lisp family as impractical.