There's a simple answer, but first, the complex caveat.
Don't read too much into this. We don't know, and can't ever know, exactly when a suggestion will first be looked at, or when we'll have gotten all the useful information out of it, so that it can be discarded.
But remember, "getting all the useful information out of a suggestion" doesn't necessarily mean taking any particular action. It MIGHT mean listing that site in that category, or another category, or in multiple categories. It MIGHT mean listing another site instead. It might mean listing nothing. And, because there are so many things an editor might do as a result of a suggestion, you can't look at the directory and tell whether it's been fully utilized. (Even looking at the logs, we can't tell what all an editor (or various editors) did as a result of that suggestion!)
So, there's nothing magical about "six months" -- no priorities come, no deadlines pass, no options expire. And there's nothing magical about "seeing a site in a particular category" -- that might not be what would EVER happen with a particular suggestion.
All clear?
But the guidelines DO allow for a site to be ONCE re-suggested if it hasn't appeared after an interval, and six months is not an unreasonable interval to wait.
There's no moral imperative -- chances are very small (order of 1%) this will make a difference.
But, yes, you MAY resuggest after waiting six months. Which is to say, it might even help, so nobody will be irritated by it.
So, what's the practical difference between all that and just saying "yes"? None. But the perspective is everything. With the right perspective, the practical issues are easy to resolve.
