You're missing the import of what Nigel posted...
The IDE interface is a multi-pin interface with various signals delivered to/from the various pins. The standard desktop (3.5") IDE interface has 40 pins plus 4 additional power pins in a separate connector (+12VDC, +5VDC, & 2@0VDC); laptop (2.5") HDD interfaces are 44-pin and include the power (+5VDC & 0VDC) pins within a single connector.
The USB interface is a 4-pin interface -- +5VDC, 0VDC, +DATA, & -DATA.
The device to which you posted the link includes special convertor circuitry which accomplishes translation between the IDE interface and the USB bus. This is much more than a simple "wire adapter", as the multiple IDE pins must be monitored and their signals encoded for transmission on the USB bus and decoded upon removal from the USB bus.
If you are interested in reading further, look **broken link removed** for pinout info, and
here for IDE operational info. The site at second link will also provide some USB operational info if you look for it...