I interpreted this as “there is an even chance of the Singularity falling before or after, [assuming it does]”. That is, if you think the probability that the Singularity will happen is something low like 1%, you should answer a year such that the probability it happens by that year is 0.5%. The only way you can’t answer it is if you’re sure it won’t ever happen.

(For example, if I thought a Singularity is very [...] very hard to achieve, I might answer 5000 AD or 500000 AD, depending on how many “very” there are, even though I might put a very low probability on our civilization actually surving that long.)