At 1/3 I think it's smart. I would have assumed a much worse male to female ratio without that.
I agree, I was also assuming a worse ratio. However, I tried comparing this with other dating sites and they report better ratios. At the same time, I suspect that FIRE community might be biased towards males (even though I heard that majority of Mr Money Mustache followers are women).
It's a really smart move regarding sustainable growth. Males will refrain of signing up without an "healthy" ratio. Not doing it would just cause early abandonments and decrease goodwill. Everybody wins.
I personally perceived this as a signaling to female users to motivate them to join more. But the way you phrase this is also interesting.
To be fair, the ratio was not public at the very beginning.
To be honest, everyone was always asking for this. I already had a public stats page back then, so it was very easy to just include it there (to save my time calculating this manually).