I don't disagree with the idea that people can be a little kooky about FP, but the idea that webapps are perfectly fine without modern front end approaches is a bit exaggerated. Managing UI state is much easier in the client - sure, if you don't have a stateful UI to begin with don't go build some JS SPA. But I've have been there done that with teams and companies that dislike JS then try to fake UI state back and forth from server to client, and it really sucks, overcomplicates stuff that should be simple.