It’s right, sort of.
USB power historically was low power / high power, IIRC something like 100mA and 500mA. The low power spec is essentially trickle charge, and USB should negotiate higher power ‘intelligently’ as needed. In this sense, yes, you need a high power charger.
However. There’s also now a thing called a Dedicated Charger Port, which is higher power. This is what the iPad uses, IIRC the plug supplied with it is a 1A device, and the USB spec goes higher still (up to 1.5A I think). Do you need one of these? No.
EDIT – the link above mentions the Kindle Fire, which is an Android tablet rather than a Kindle ‘proper’ – it looks like this does need a DCP, but it’s an exception.
On the upside, pretty much all USB mains charger plugs are high power devices (and your laptop USB port should be too). I’ve not seen one that isn’t, at any rate. So whilst the advice you’ve been given is technically correct, it’s a non-issue in practical terms.
I think.