The truth is you take on risks any time you buy something used, such as a used car or items from a yard sale. Unfortunately in today's disposable society we often unknowing take the same risk with new items, like runaway Toyota's, etc.
I read an article called 10 things you should never buy used and one of them was a laptop because you never know if they may have been dropped. Shipping products in the mail adds an extra concern of damage in shipping whether the item is bought new or used.
I do believe eBay has improved their buyer protection policy but I also believe human greed and indifference to our fellow man has increased significantly and buying online helps facilitate its' ease. It is a lot harder to look someone in the eye while you stab them in the back then it is from 3000 miles away.
eBay knows full well there are numerous categories where fakes run rampant and like almost every company today they put their profits above the welfare of the people. Walmart likes to keep most of its' staff working under 30 hours so they are considered part-time and therefore are not required to offer them benefits so we can buy cheaper products at the expense of thousands of workers yet very few think or care about that. Google sells it's own subsidiaries intellectual property in Ireland and offshore islands to avoid billions in taxes and that is not stealing it is just "good business" (other multinational companies do this as well, Google just seems to be the best at it).
I received an email from a lady I know in Australia that said to boycott Hershey's chocolate because it is now made in Mexico; I live only an hour away from Hershey, PA and I know that the workers agreed almost unanimously to a loss of about 450 workers so that a new automated plant would be built right outside of Hershey rather than move all production to the Mexican facility. If you stop buying Hershey's then those 1100 peoples livelihoods are also in jeopardy.
Companies used to be made up of people, now they are seen as entities too big to challenge and they buy and sell congressmen to look the other way or even tip the scales toward corporate greed. We so distrust all politicians and feel there is nothing that can be done that we have grown apathetic. It is a common joke, "How can you tell when a politician is lying? Their lips are moving!"
You won't solve what is wrong with people, or America, or the world by avoiding eBay, or Google, or Hershey's, or politics. It will take individuals armed with knowledge and a willingness to make a difference.
... I'd run for office myself but I'm too busy Googling the best price for a giant Hersheybar that I'm watching on eBay