Whiny is the word that comes to my mind.
Product gets listed. Seller sells it to the best legitimate offer (not even necessarily the first one).
In other words it's business.
I think there is a difference between a buyer contacting a seller, and someone seeing a post saying "Hey, I'm going to order this today" and contacting that person with a "hey, want to buy mine instead?"
Azuremen, you also made an offer that I felt was too low. I'm sorry you disagree with how I do business. I get low balled everyday when I'm working and it just wastes my time. I'm not going to start into negotiations with someone who offers a lower price when I feel that my price is fair. And not only that, but multiple people are wanting to pay my asking price!
Then don't contact people asking they'd be interested in buying your stuff in the future. Considering, new and shipped, from PChome is coming out to under $140 with keycaps and such. I offered what I felt was reasonable (given that I've seen Tenkeyless go for 110 here) and said it was negotiable.
Business is business, but you could've bothered with "hey, I feel it is worth more and I'm going to list it."