It's not only your personal observation (though I would remove the "purely" from "purely functional languages). A good indication of that: on the Go 2020 survey, the 6 most popular responses to "Which critical language features do you need that are no available in Go?" are features that functional programming languages have. All of these features are in ML and its descendants (SML, OCaml, Haskell, Scala, etc).
The graph: https://go.dev/blog/survey2020/missing_features.svg
The article: https://go.dev/blog/survey2020-results
In a way, you can see that the people using these languages that may appear very different are converging to the same "ideal". And that's not a surprise, both languages have a very Unix-y origin, and origin in Pascal/Modula. Go added to that CSP, OCaml added ML. These days OCaml is adding things to better handle the CSP part, and some people are asking for Go to better handle the ML part.
> This attitude I think is the reason most experienced deveploers I've worked with are put off by the language.
This is not my experience. Of the six team leads with whom I've discussed the language (after they've had some experience with it) only one was put off by it. The rest were either glad that “something simpler is finally here” or were of the opinion that Go is “just another language”.
(Interestingly enough, the one person who was not impressed was a big fan of purely functional programming, while all others were C++/Java/Ruby kind of people. Which is consistent with my own personal observation that fans of purely functional languages tend to dislike Go, for the most part.)
[1]: https://research.swtch.com/vgo-eng