I'm not a fan of Go, but I have to admit that benchmark doesn't make any sense. If you use tail calls in a language that doesn't support TCO, then of course you'll get bad results.

I guess its easier to just throw in some numbers than compare idiomatic implementations and then discuss tradeoffs with some nuance.

Even if its just a language teaser, I'd still add a note on TCO to avoid misleading people though.