I never mentioned 20% I am glad you could read between the lines and extrapolate that out of my post. That takes a certainly subtlety I am not usually capable of.
Josh – You are correct, you did not say 20%. I stand corrected. I got the 10-20% down from the original post, not yours. I assumed (wrongly, I suppose) that you were implicitly suggesting from your response that you would expect a buyer to save that much down.
Regardless of the number, there are plenty of reasons not to save for a down payment if the market provides 0% to 10% down.
Another example. Joe NewHire gets a new corporate job and has the option to put 25% of his income into the company 401k or saving the equivalent in after-tax income towards his down payment. I would have to advise him to put it into the retirement account rather than save for a down payment.
In any case, I think your general message of fiscal responsibility, with which I would agree, was somehow lost in the name-calling.