The charger is doing what it should, it loads with max. 1000 mA a device with mini-USB jack. For a MP3 player or a cell phone that is perfectly adequate. Especially for devices that are delivered without Charger is a charger indispensable. One example will not similar with the laptop / netbook to MP3 Player load that is too unwieldy on vacation.
For a tablet you should choose a charger with more charging current.