The same way Stupid Quesions beget a Stupid Answer,
Lower Ball Offers beget a Low Ball Reply.
Did the Offerer really think it was cool to offer $1000 for clothingstore.com?
Not to insult owners with unsolicited offers, ignorantly or not, I simply send an e-mail asking If the domain is for sale and What are their price expectations.
If one really wants the name and is a player, then they can start negotiating from the owners reply price. If one does not have the $ to buy the name in the first place, at or around the owners price expectations* then yeah, stop wasting everyone's time. (*Note: As long as Price Expectations are around Fair Market Value that is, and not overly inflated.)
I find not insulting the owner increases my chance of getting the domain I want.
(...but maybe that's just me.)
Personally, I just don't respond to low-ball offers. I don't have time to reply with my price to 100 low-ballers on the off chance 1 may result in a sale to a real businessperson.
IMO, low-ball offers are like spam -to most recepients, it is a waste of time, but to most senders, it can result in 1 sale, and that's enough to justify wasting everyone elses time.
Best of Luck with Your Endeavours!