I sell CDs all the time. It doesn't bother me at all. I've re-purchased probably less than 10% of the ones I've sold such as Fear Factory, Clutch, Type O Negative, Neurosis and a few others, so it doesn't bother me.
I'd rather someone that is actually going to listen to it own the CD instead of taking up space on my shelf. Plus, the money I make from selling CDs buys me the ones I actually do want.
It's my own fault that I sell them, because when I find a type of music I like, I go hog-wild and buy every band in that style. Then, a few later I only end up listening to the better bands, and have no need for the second tier bands. The last genre I did that with was the -cores, and now I'm unloading a few of them. Now I'm into doom, but I'm being very selective thanks to Erik.
That being said, I re-purchased Shadows Fall's debut and ended up selling it again, realizing why I sold it in the first place. I sold it as "brand new, unsealed", hehehe.
NAD, I'm surprised Jaykeeley didn't demand you pay him to take Dimmu off your hands. It's that bad.