As the others have written so far, other members cannot see what you have bought, by just looking at All feedback, or feedback as a buyer. However, since you often say what you bought in the feedback you leave for others, dino eggs, pyrite, fossils... Then people can look up the purchases from the seller's feedback profile page. If you want to hide purchases you bought to resell why not start an account just for buying, and use this account for selling only?
Since you do sell items that are fairly commonly listed items on the site, not adult in nature or health related. Making your listings all private may put some buyers off. They would want to know if you are experienced at selling fossils, mineral specimens, and other things.
Also blaming those who had issues with items you have sold, and calling them names, makes you look bad as a seller. If you were not contacted about an issue before feedback was left, it is fine to say that, but stop there. Adding comments saying something is wrong with their player or anything else is not necessary. Leaving feedback saying you had to get ebay involved is a policy violation, and makes your comment eligible for removal.
"THERE IS NO SUCH THING AS FOOLPROOF, BECAUSE FOOLS ARE SO DARNED INGENIOUS!" (unknown)
