Here is Ebay's policy-
Extended coverage high frequency transceivers: Equipment that is intended to operate in various radio services in the high frequency radio spectrum, including "10-meter" Amateur Radio Service (ARS) equipment, can be listed. However, sellers can't list high frequency transceivers that are designed to operate on frequencies outside of the ARS bands unless the transceiver has been issued a grant of equipment authorization by the FCC.
Granted people may not like the restrictions but again they are a private site that has chosen to try to incorporate FCC guidelines in their restrictions. People don't have to sell there. It is up to the seller to make sure his item is allowed to be sold on their site. If they go ahead and list it they take the chance of it being noticed and pulled.
- CB amplifiers: Examples of items that aren't allowed include:
- CB amplifiers
- Amplifiers specified for use on the 11-meter band
- Amplifiers designed for use in frequencies 24 MHz to 35MHz
- Amplifiers posted within the CB category
- CB radios that are amplified to exceed 4 watts using the AM settings or 12 watts using the SSB settings